Had a game where the DM and his bestie homebrewed Roy Mustang. The PC was insufferable and overpowered by level 3… shooting fireballs that consumed the entire room in a single attack.

The party, and the group, broke up because they were mad the rest of us didn’t want to live in their power fantasy world

Hear me out: I played with an orc fighter who was convinced he was a mage, and tried to convince the rest of the party of the same thing. He carried a cast iron pan as his weapon, and his spells were "pan toss" and "pan smack". There were a lot of laughs when NPC's would be like "you're clearly a fighter, you're wearing plate armor" and he'd say it was his spell casting focus.

i had a rogue that i claimed to have forgotten the name to each session. in reality, i was playing them under a false identity and hiding from the thieves guild, that was just me dropping bread crumbs. that was fun.