My memory is not the greatest, but nostalgia keeps trying to tell me playing Sonic Mega Collection on gamecube while also switching back to TV mode when commercials ended was one of the best gamer moments for me.
But I know that it surely must be a more current thing like me defeating the harder boss battles in the latest update of the pokemon fangame Pokemon Rejuvenation, good route, within the last month or so. Classic mode difficulty isn't a joke, even with facing zero IV pokemon with no enemy item usage thanks to the password system, if you are like me and still try to be a bit casual in your playthrough.
That makes my achievement of beating a Pokemon Reborn randomizer run ( not NPCs ) without resorting to legendaries, mythicals, or pseudos look like a playthrough of Pokemon Emerald in terms of difficulty, IMO.