I'll just throw this out in the middle of this conversation about Stevens and why the Celtics team "quit."
Well, maybe they quit just like the current Red Sox team has "quit."
Because they felt the management was not supporting their efforts to win.
The Celtics got that immediately at the start of the season with Hayward coming out of the blue into the starting lineup. Especially after the Celtics had almost gotten into the finals last season without Hayward and Irving. To say nothing of Hayward, even Irving wasn't 100% ready to start the season with a heavy load. But both were in the starting lineup as if nothing had happened down the stretch. And Stevens spent much of the pre-season, not on the starting lineup, but on who was going to be the last players to make the team.
The Red Sox players maybe got that in spring training, when the team was "resting" players , which they had done successfully last September before the October playoffs. But that was September, not March, and they had already clinched the division and best record, for all intents. And then they stonewalled Kimbrel, instead bringing in a slew of AAA releivers and castoffs to fill the bullpen (they are still doing that). Granted they were up against a cap wall, but Henry made a fortune on the Red Sox last year, and they deserved better than his going cheap on them. There's a pic on Twitter today of Henry flying first class holding some soccer champion cup up with his hands. It's no wonder the team is flat.
The similarities with the Celtics are there. If the players (even some of them) think the management is not putting out its best effort to win, they won't either.