If you had to narrow it down to one what-if per franchise, which one makes the cut?
I'll give examples using the team I support (the Celtics):
Injuries - KG's injury in 2009. The Celtics had a scorching start to the season, but lost in 7 to the Magic. KG's absence let Dwight loose on the boards, & the next year when they did make the finals the Big Ticket had clearly lost a step.
Deaths - Len Bias in 1986. Red Auerbach had drafted a potentially transcendent player to back-up the greatest frontcourt in the history of professional basketball. Instead, a cocaine overdose killed him hours after being drafted No. 2.
Draft Picks - Kedrick Brown in 2001. Know who the Celtics had wanted to draft? Tony Parker. Unfortunately then-GM Chris Wallace was overruled by Celtics patriarch Red Auerbach.
Suspensions - Ime Udoka in 2022. Just months after taking the Celtics to the NBA finals, the former Spurs assistant was suspended for inappopriate relations with a female employee.
Made/missed shots - Artest's 3-pointer in 2010. I will always believe we'd have stolen that game if ~~Ron Artest~~ Metta World Peace doesn't drive that dagger through our hearts.
Not that big a deal, but the refs clearly miss called a Draymond 3 as a 2 in the last game of the 2019 finals. It would have been tied with 12 seconds left if the Warriors had one more point when they started fouling to get the ball back. I suppose various injuries were bigger, but that was a reviewable call, and they didn't, and it was clear on replay that he was behind the line.