https://screenrant.com/actors-who-shockingly-quit-hit-tv-shows-list/

Reasons for leaving their successful TV shows vary, but what some actors have in common is the way they took audiences by surprise when they left.

Jim Parsons being #1 on this list is ridiculous. Everyone else on it left and the show continued without them. And I wouldn't consider his wanting to end TBBT shocking either. Most sitcoms don't last twelve seasons, over a full decade. Burnout is natural after that long.