I mean, a lot of the time its just how the DM runs the game. They make it a meat grinder and the players go in expecting a meat grinder, so you get a full table of That Guys because... otherwise your character gets turned to paste inside the first ten minutes of the game.

I remember the RPGA in college and it absolutely minted "That Guy" players because so many of the DMs were just in it to collect scalps.