The part at the end of DKC when Donkey and Diddy are at the treehouse having fun with each other is quite heartwarming.
Earlier, when they enter the banana hoard (that room that normally triggers the "failure" cutscene due to the entire stash of bananas being stolen) and find they huge mountain of bananas returned to them.
When Skurvy and Klump are reunited in the show.
When you 102% Donkey Kong Country 2, Cranky swallows his pride and admits he was wrong about Diddy not being cut out to be a game hero. He goes on to say he must take after himself and DK, subtly complimenting both of our favorite apes at once.