I've always enjoyed writing dim-witted but cocky characters who think they're cool, but fail at every turn. I used to write a lot about a girl named Vandalgeist who surfed on a hoverboard and styled herself as a very "cool" punk. And then the one and only time I played D&D, I made a very similar tiefling named Betty who was a constant liability to her team and liked to become a rat for no reason. Good times...
I guess my most recent version of this character is Jeff from my comic StarCrash!! with Jeff. He's like the quiet, shadowy version of Vandalgeist, but just as misguided and cocky and insecure