When the Celtics win, the Green Teamer contingent of Celtics fans love to mock the other side, by saying "See you're an idiot." And when the Celtics lose the other side likes to "See blow it up! Fire the coach." The rest of more sane fans in the middle are more nuanced.
If the Celtics fall to the Heat in this series, they aren't going to blow it up and trade everyone, hire a new coach, and start over. They will either put the blame on head coach Joe Mazzulla and make a change or the playes and make some changes there.