Elden Ring - Beating Malenia Blade of Miquella

Getting the fully powered suit in Metroid Zero Mission. If you know, you know...

Seeing those sweet, sweet credits roll.

That is certainly a hot take. I would never think of the credits as the sweetest moment, unless I did not like the game. I was glad for the Horizon Fobidden West credits. But usually I am sad it is over.

For me, I'd say the ending of "The Last of Us 2", that conversation is really moving and incredibly well acted. In addition, within the space of 2-3 minutes, it manages to encompass and signify the entire theme and mood of the game itself. Brilliant scene.

My GF is the same way. She doesn't want to see her shows, games and books end. Sometimes, because of this, she even intentionally doesn't finish them haha.

But for me, I view beating a game as an accomplishment. Same with finishing a book. You stood before the mountain, you accepted the challenge and you conquered it, that sort of thing. So in that context, the credits are basically the money shot; the proof you've succeeded. 

TMNT II: The Arcade Game

Super Mario 64

Ghosts 'n Goblins

Most recently FFXVI.. scene with Clive and Jill (big spoilers ahead!)

There are exceptions, like the ones from MadWorld, which are funny AF:

Gotta say FFXVI is filled with some heartwarming moments.