I'd say the trophy sound that pop's up, on ps3. I never paid much attention to the way it sounded on ps4, or ps5.

As for in game moment, the sweetest moment, as in pure bliss/joy/happiness, it might be the final level of the game flower, the end part to it.

Awesome pick! Definitely also my sweetest moment in "flower". Don't know what moved me so much, but I cried through the whole ending section. Perhaps even one of the all time top 20 sweetest moments in gaming.

When Slippy Toad didn't make it. - StarFox 64/Lylat Wars.

Wind Waker turning Ganon into stone via master sword.

Not an old gamer (only started in 2017) but…certainly the sweetest moment I’ve had to this point would be when I finished my first competitionist run of SMOdyssey. Took over a hundred hours! And I saved the dark side for last. Really such a great way to “cap” off the game with the Odyssey giving that full golden glow, the (albeit “cheesy”) dialogue as you climb the castle, the reward that comes afterwards. So good!

for me it's Vagrant Story. Seeing Sydney Losstarot get his just due was enjoyable. Only sucks that Ashley Riot wasn't the one to do it.

Beating Gary at the end of Pokemon Red and Blue after putting up with him being such an insufferable prick for the whole game.