My guy syndrome?

There's more than the two alternatives of playing "Myself, a person who games a lot and knows things a veteran gamer would know, but with D&D powers" and "The personification of chaotic stupidity that is my alter-ego, an insufferable piece of shit, but with D&D powers".

The "My Guy" syndrome is the inexperienced person's experimentation of Improving in RPGs. The meta-gamer is the experienced-but-tactless person's desire to play the game straight up as a board game, rather than a social experience.

There's a third - even more experienced - kind of player, who can seamlessly integrate the rules they're very familiar with into the story of their character that they're trying to tell. The player who says "I'm going to play a kleptomaniac Rogue" and proceeds to steal the belt off a rampaging Ogre to trip him with his own pants as a combat maneuver. Or the player who says "I'm going to play a Stubbornly Self-Righteous Knight" and is as rigid in his morals as he is tankie in his ability hold the line when the party needs it most.

These players lean into their conflicts for a comedic interlude, then squad up to form a deadly duo when its time to crack heads. And that makes the game both more fun for everyone at the table (especially the DM) than someone mired in the technicalities of a feat description or obsessed with being the center of attention.