Most are just kinda boring
The guy who runs a module but doesn't read more than one page ahead. Ignored half the actual cool stuff the module had and didn't bother fixing the bad. (I read it afterwards)

The guy who just kinda runs things on fiat without knowing how to put any sort of interesting decision in front of the players.

The guy who has the apocalypses start all of a sudden on session 2/3 but didn't actually plan for us to do anything during the apocalypse.