You know the invigorating feeling of a new NBA season, when optimism spills forth from the cups of (nearly) every fanbase and, to spin a phrase from legendary orator Kevin Garnett, anything feels possible?

Well, life gets different in the dog days. It's halfway through the 2021-22 campaign, and optimism is—like most commodities nowadays—in short supply.

My cup isn't even halfway empty; it's borderline bone-dry, and the few remaining drops are ice-cold.

The purpose here is to disperse those frigid drops onto the season's biggest disappointments, subjectively ranked based on significance, their likelihood of lingering and the level of change they could produce.

10. Too Much Missing Talent

Anyone else feel the electricity bursting out of Klay Thompson's return Sunday night?

I wasn't inside Chase Center, but I didn't have to be. The energy zipped out from any streaming device all the same, and when he marked his return from a 941-day absence with a mean-mugging rim-rocker, it felt like all was right in the basketball world.

That's because, if you can believe it, a league defined by its superstars is best when its galaxy is illuminated by a full complement of stars. But that hasn't come close to happening.

Kawhi Leonard, Zion Williamson, Jamal Murray, Jonathan Isaac and T.J. Warren are among the players who have had their season debuts delayed by injury. Ben Simmons hasn't suited up because of an unfulfilled trade request. And those are just the players who haven't logged a second. Add in those who have played but since lost time to injuries or the health and safety protocols, and you'll basically have a group of the current greats.

Nothing can be done about this, so it wouldn't feel right to rank it any higher, but given that it's a 12 out of 10 on the bummer scale, it needed an acknowledgment.

9. The Breakout That Wasn't

No one entered the 2021-22 season with a buzz quite like the one draped around Michael Porter Jr.

He scored a five-year max extension before the season tipped. The Most Improved Player award was his to lose. He was the single biggest key to the Denver Nuggets surviving Jamal Murray's absence, a void that freed Porter to gorge all-you-can-eat style on scoring chances.

He had the "all clear" to take flight, but he never made it off the runway. He averaged more shots (12.4) than points (10.9) over his fight eight contests, undone primarily by a wholly uninspiring 36.4/21.7/55.6 shooting slash. He didn't make it through his ninth game, exiting early with a back injury that eventually forced him under the knife.

Injuries are an unfortunate part of NBA life, but this carried a particular disappointment. The Nuggets had just bet the farm on Porter, and they badly needed him to deliver with Murray down. For Porter to fall victim to the same thing that previously troubled him—his would-be rookie season was wiped out by college back surgery—felt like a particularly cruel gut punch.

He came into this campaign with all the makings of a rising star. He'll exit it with serious questions of whether he can ever make good on his potential.

8. The 'Bockers Backtracking on Offense

The New York Knicks needed more scoring threats around Julius Randle. Anyone who caught a second of last season's first-round loss to the Atlanta Hawks could've reached the same conclusion.

New York spent the summer searching for buckets. Internal weapons like Randle (four years, $117 million), Derrick Rose (three years, $43.6 million) and Alec Burks (three years, $30 million) were paid a premium. External upgrades in shot-making (Evan Fournier on a four-year, $73 million deal) and shot-creating (Kemba Walker for $17.9 million over two seasons) cost a fortune, too.

So, what did the literal hundreds of millions net the Knicks? A two-spot slide in offensive efficiency rankings (22nd to 24th) and 2.2 fewer points per 100 possessions.

Randle might be turning back into his pre-All-Star pumpkin. Fournier is having the third-worst shooting season of his career (54.1 true shooting percentage). Walker's erratic offense and leaky defense cost him a rotation spot. Burks has been meh. RJ Barrett has backtracked. Rose looked good until his latest bout with the injury bug resulted in ankle surgery and possibly a two-month recovery period.

7. Washington's So-Called Snipers

What if I told you the Washington Wizards were dead last in made triples and 27th in three-point percentage? Would you be absolutely floored by that?

Maybe not, since Washington sat 28th and 23rd respectively in those categories last season.

But then you'd start to think...Wait, didn't they give Davis Bertans a five-year, $80 million deal last summer just to efficiently shoot threes? And didn't they just spend the 15th pick on another shooting specialist in rookie Corey Kispert? And, hold up, wasn't their leading scorer Bradley Beal an absolute fire-baller from three not too long ago?

Yes to all of the above, but the investments have yielded almost nothing. Hence, you can now appreciate the degree of disappointment here.

Washington has just two regulars shooting better than 35 percent from three: Kentavious Caldwell-Pope and Aaron Holiday, who rarely lets it fly from range. Bertans' 34.1 percent clip is by far the worst of his career, as is Beal's 29.8. The best thing to say about Kispert's 28.6 percent splash rate is there is (hopefully) nowhere it can go but up.

6. Boston's Failure to Finish

When oddsmakers assessed the Boston Celtics before the season, they pegged them as a 46.5-win team. After dropping five of their last eight outings, the Shamrocks are instead on a 39-win pace.

What went wrong? Well, no shortage of things—most primarily connected to the offensive end—but the clearest culprit might be the Celtics' inability to close out opponents.

They have entered clutch situations (final five minutes with a scoring differential of five points or fewer) 23 times and lost 16 of those contests. They have already lost six games they led entering the fourth quarter and have a minus-7.8 net rating in the final stanza. They have blown 19-plus-point leads four different times.

"I think it's a lack of mental toughness to fight through these adverse times," Celtics coach Ime Udoka said, per ESPN's Tim Bontemps.

There's no one area of focus, as untimely breakdowns at both ends have undone this club. The good news is the Celtics are getting something right to build these advantages. The bad news is there isn't an obvious way to protect them.

5. Zion Williamson Watch

Remember when Zion Williamson was possibly going to suit up on opening night? Deep sigh.

A half-season later, he's nowhere to be found. Well, he's nowhere near the New Orleans Pelicans at least. ESPN's Adrian Wojnarowski, who could sleuth the whereabouts of Carmen Sandiego if he had the time, learned that Williamson has taken his rehab from a fractured foot up to Portland.

Two years back, the Pels waited until late January for the then-rookie to make his season debut. He could easily miss that mark this time around, as there are no updates regarding when (or, let's be honest, if) he will hit the hardwood again.

That's a brutal blow for New Orleans, which has unsurprisingly struggled without its focal point. The Pels looked capable of at least being competitive and maybe much more if Williamson's star really shined. Instead, they're floundering without him, and Williamson is turning analysts into literal weight watchers. Deeper sigh.

4. The Superteam Stuck in the Play-In Tournament

Skeptics will say they saw this coming. That they thought the Los Angeles Lakers had mismanaged their roster and failed to construct a legitimate championship contender.

Pshhh!

It's one thing to question the fit of Russell Westbrook on a team that arguably (clearly?) needed spacers more than playmakers. It's quite another to label a squad with LeBron James and Anthony Davis as anything less than a championship threat.

Oddsmakers believed the hype. They penciled in the Purple and Gold for a Western Conference-best 52.5 victories. If the Lakers could sustain their elite defense and see their offense perk up with Westbrook's open-court attacks, they had a clear path to the top.

But the defense has dropped to the middle of the pack, the offense hasn't gained any ground and the Lakers have struggled to find anything they're great at beyond rostering King James. L.A. is 10 games back of first place in the West and five games from falling out of the play-in tournament. The Lakers could still make noise with a healthy Davis, so they won't rank any higher here, but so far, it's a sad way for James to spend his 19th season.

3. Hawks Having Their Wings Clipped

When the Hawks forced their way into the Eastern Conference Finals last season, they followed the lead of the under-25 trio of Trae Young, John Collins and Kevin Huerter. With three more core members in the same age bracket (Cam Reddish, De'Andre Hunter and Onyeka Okongwu), it seemed Atlanta could soar atop the conference—if not now, then in the very near future—and stay for a while.

The Hawks haven't looked the same since losing that series.

The offense is absurd, but the defense should never be directly viewed by anyone who gets squeamish easily. It's fourth-worst in the league and leaky enough that Atlanta has a negative net rating (minus-0.5) despite owning the third-most efficient offense.

"It's frustrating. It's not fun," Young said, per The Athletic's Chris Kirschner. "Being one of the best offensive teams in the league is a really good thing, but when you're letting teams score as much as you, it's not good for the team. We got to figure it out."

Atlanta figured it out well enough last season, when it landed a serviceable 18th on defense—nine spots better than now. And before anyone singles out Hunter as the missing piece (out since mid-November after wrist surgery), he was just as absent last season (23 appearances, 19 starts). The Hawks should be better than this, but they just aren't, and that could ground their return flight to the postseason before it even leaves the gate.

2. Cracking of the Rock-Solid Pacers

The Indiana Pacers have ranked among the most reliable teams in recent history. Prior to last season, they had made five consecutive playoff appearances and been knocked out of the first round every time. That run was sandwiched in between seasons with winning percentages of .463 and .472.

That looked like an absolute worst-case scenario for this season. The Pacers upgraded at head coach from Nate Bjorkgren to Rick Carlisle, had Caris LeVert in their program (not forced to adjust after a trade) and added instant-impact rookie Chris Duarte, who's been even better than advertised.

So, why isn't this working? Why does Indiana have its first sub-.400 winning percentage in more than a decade and worst since 1988-89? Why did this team, a realistic candidate to climb in the Eastern Conference, spawn rebuilding rumors less than two months into the season?

It's a mess in the Circle City. The offense is forgettable. The defense is bad. Any pressure to perform torpedoes this team; it's an impossibly bad 1-9 in games decided by three points or fewer and owns a minus-27.8 clutch net rating.

The Pacers probably aren't completely pulling the plug. They don't want a demolition. Maybe the right amount of reshuffling will help this roster find its footing. The hope for improvement keeps the Pacers from being the most disappointing team around, but the disappointment is severe enough to think this nucleus is on the cusp of permanent change.

1. Damian Lillard and the Tragic Trail Blazers

On the heels of four first-round exits in five years, the Portland Trail Blazers decided being good was no longer good enough.

Whether motivated to move by Damian Lillard questioning their championship credentials or simply out to snap their string of brief postseason cameos, Portland made some tweaks. Longtime coach Terry Stotts was let go and replaced by Chauncey Billups. Next came a three-team trade for Larry Nance Jr. Then, following an investigation into workplace conduct, came a split from president of basketball operations Neil Olshey.

The Blazers wanted to be better, but they stopped short of making wholesale changes (for now, at least). The undersized, offense-focused backcourt combo of Lillard and CJ McCollum remains. Same goes for frontcourt holdovers Jusuf Nurkic and Robert Covington.

Process-wise, Portland still looks like Portland: substantially better on offense than defense. But with a hobbled Lillard unable to summon his typical superpowers (24.0 points on 40.2/32.4/87.8 shooting), the offense has sagged from elite to average, while the defense remains disastrous.

The Blazers, who, before the season, appeared through squinted eyes like a squad capable of being at least a plucky playoff opponent, could now be on the cusp of punting the campaign and starting over.

A megadeal for Dame doesn't seem to be in the cards yet—if Portland is comfortable giving the 31-year-old a two-year, $107 million extension next summer, it can probably keep him happy—but everything else is on the table.

The Blazers pushed for change, and they're getting it. It's just not the change they had in mind. Instead of an all-out postseason pursuit, Portland might have to welcome a trip to the lottery, both to rest Lillard (and hopefully get him right) and keep its lottery-protected 2022 first-rounder away from the Chicago Bulls. Because if that doesn't work, the nuclear option of a Lillard swap might be the only card left on the table.

Statistics are accurate through Sunday's games and courtesy of NBA.com and Basketball Reference, unless otherwise noted.

Zach Buckley covers the NBA for Bleacher Report. Follow him on Twitter, @ZachBuckleyNBA.