For a long time, it was Donkey Kong Jungle Beat. The original Gamecube version, with the bongos. Something about beating a pair of drums for an hour two was terrific stress relief, and the game has such incredible energy that I always came away from a play session feeling really good.
Old school first person shooters can be that way sometimes, too. No story to worry about, just running around blasting everything that moves.
Childhood games are, of course, probably the king in this regard. Donkey Kong Country 1, the SNES version of Aladdin, Yoshi's Island, Sonic 3 & Knuckles, Super Mario 64, NiGHTS, Chrono Trigger, Earthbound... big comfort food vibes from those games.