The Sixers added another stinkbomb to their collection of smelly basketball crimes on Thursday night, losing 124-104 to the Celtics in a game that was never close.

Here’s what I saw.

The Good

— The game ended.

The Bad

— Philadelphia’s offensive process has been better of late, in part because they have the personnel to force mismatches and in part because they’re trying run plays. That’s unfortunate because they have essentially collapsed on the other end of the floor, which is what held them together during a brutal start to the year. So all of their gains on offense are being given back to their opponents, essentially.

It’s hard to view many of their problems as anything other than self-inflicted. Payton Pritchard is a leading candidate for Sixth Man of the Year this season, and he is burning the nets down from deep (Pritchard was shooting 41 percent from three on almost eight attempts per game coming in). The entire team seemed to be unaware that was the case. On several occasions, players cheated off of Pritchard one pass away, with Andre Drummond basically walking away from him on one possession before Pritchard stepped into a wide-open three.

Structurally, you have to start from a place that makes sense when you consider who the other team is playing and what their strengths are. Zone defense is mostly meant to prevent teams from getting to the paint, and the key to beating it is as simple as shooting a team out of it. While it’s certainly possible to play effective zone defense against the Celtics, encouraging them to take more of the shots they already chase with reckless abandon is a dumb approach on paper.

Something like 50 percent of my beef with the Sixers this year can be summed up by that “dumb approach on paper” idea. It was my issue with playing Kyle Lowry long past his expiration date. It was my issue with playing four-guard lineups with three bad defenders. It’s my issue with letting the Boston Celtics have a goddamn shooting gallery on their first night back after the All-Star break. Even if you dumb luck your way into success for an odd night here and there, it isn’t sustainable.

There’s also the matter of trying to get everyone on the same page with what they’re playing. Embiid is a big defensive chess piece, someone they change coverages for and funnel drivers toward. But the Sixers repeatedly botched that on Thursday night — they often funneled Boston players toward no one at the rim, with Embiid out on the perimeter guarding a stretch big or switched on a smaller player. Even when they had him back there, Embiid had problems of his own we’ll get to below.

The most infuriating problem is their complete inability to get set up in early/transition defense. They have constantly looked like a team with no idea what their assignments and principles are. Like many other teams this year, the Celtics walked into open jumpers early in the shot clock, including off of dead-ball plays, when there should be greater clarity about who to defend and where. Keep in mind, it’s late February, so even with new additions to the rotation, it’s hard to take excuses about continuity seriously if that’s meant to be the explainer for why they play headless chicken defense this often.

Just a complete trainwreck.

— Joel Embiid has been decent on offense in his recent performances. Not MVP good or really all that close, but good enough to be part of a successful offense when everything is clicking.

The issue is that “decent” is not good enough to warrant having by far the majority control of the offense. Tyrese Maxey was on an absolute rampage for most of January and gave people a reason to continue investing in and watching this team despite the misfortune they met at every turn. And while Maxey had a good, effective game on Thursday night, there were stretches of the game when he felt like a passenger, standing around watching Embiid operate out of the post.

Nurse’s decision on how to sub it played a part in that. Maxey’s minutes in the first half were almost exclusively tied to Embiid’s, which didn’t give him much runway to be the undisputed king of the court with bench lineups. Although Maxey has terrific chemistry with Embiid and can use the attention he draws to light it up, Thursday’s game didn’t capitalize on that dynamic all that much, relegating Maxey to sidekick duties too often for my taste.

In past seasons, even as recently as last year, the decision to play primarily through Embiid was more than justified. That is not the case right now.

— If nothing else is accomplished with this close to the season for Philadelphia, they should be taking a long, hard look at Nick Nurse and what he is (or isn’t) doing to lead this team. One game doesn’t tell the story of a season, but it’s at least a little bit telling that this team came out of the break with a “need every win” reality, only to take a huge, steaming dump on their home floor against a hated rival.

The players who have shown an inclination to try to fight for this season and this coach are predominantly guys in a real battle to fight for their futures. Justin Edwards on his two-way, Guerschon Yabusele in his first year back in the league, Adem Bona as a rookie, Jared McCain as a rookie, and so on. You could make a half-hearted case for Kelly Oubre, who has battled on defense, but Tyrese Maxey is the one main guy you feel okay about for his commitment to trying to get this thing right. It’s not a great sign for Nurse that he hasn’t gotten more than that.

Before we pin it all on the coach, though, take a look at the two veteran stars on this team. Paul George has been the picture of California Cool, a guy who has flashes but ultimately fades into the game and the background more often than not. We are a week removed from his two-point disaster against the Nets, and though he was more effective in this game, he certainly didn’t do much to stop the Boston onslaught/

Embiid is a much bigger disappointment there for me. He is slow rolling this season as if it is the typical 50-win year that they have had with him on the floor, and he is watching the league get younger and faster as his body creaks more and more. Individual habits that didn’t hurt him a year or two ago are suddenly popping up more destructively. Positioning on rebounds matters a lot more when you can’t or won’t jump and can’t just outmuscle guys in traffic. Your body language and how you respond to adversity — like throwing your arms up when Ricky Council IV doesn’t hit you with the immediate re-post pass — is going to have a greater impact on the team vibe when you can’t back up that frustration with an ass-kicking display when you have the ball. They need his voice, commitment to rebounding, and a lot of other dirty work that he just is not doing or doing enough.

In other words, there should be four main leaders for the Sixers on a game night. Nurse, George, and Embiid have all failed at their part of the job. Complete failure.

The Ugly

— There is no reason Andre Drummond should be playing minutes for this basketball team the rest of the way unless they are packing it in and hoping he can help them lose games. It is especially silly to play him in a game like this, against a team that wants to spread you out, slash-and-kick, and bomb away from the perimeter.

Part of Nick Nurse’s pregame chat was about where he feels they can improve their defense, with the head coach bringing up their lack of size and (by extension) rim protection with Embiid and Drummond often injured. Drummond disproved that theory in a single shift. The Celtics drew him out repeatedly, and he made the wrong decision just about every time, rarely putting himself in a position to contest on the back end. He looks like he is moving in quicksand, and his offensive decision-making certainly isn’t making up for his defensive crimes.

But here’s a bigger big man problem: to my eye, Embiid is not helping a whole lot in this department, either. At the very least, he’s not helping as much as he needs to in order to save these guys. His wheels have looked decent enough for a guy who has barely played all year, including when he is operating out of the post and hitting quick drop-step moves. But I think you can see the difference in burst when he has to try to win two-on-ones or extend to contest a shot when a guy finishes on the other side of his rim. He still has considerable size and good instincts as the back line guy, but even a marginal difference in speed and verticality can be the difference between defense and death against elite teams.

(Frankly, we don’t even need the elite team caveat. It’s not like this team has defended anyone effectively in recent weeks.)

In any case, please give me a 10-15 minute dose of Adem Bona every night. He’s going to have some foul problems and other execution-based issues, but I will deal with that in a trade for some athleticism and competitive fire out of the backup center.

— The Sixers were getting absolutely punked by the Celtics early in the third quarter, to the extent that Nick Nurse had to call timeout to throw in a couple of “let’s shake it up” substitutes. It seems noteworthy that one of the guys you took out of the game for those purposes is the man you gave $200+ million to last summer.

— Hard to believe this team has acted like they are still in the hunt coming down the stretch.

— Every time Al Horford checks into a game in Philadelphia, they should put a graphic on the screen of him with a ski mask on and an oversized bag with a dollar sign on it in his hand. Some robberies remain legal!