My pick is Five Finger Death Punch and the obvious answer is Ivan Moody. The guy radiates that alpha-male wannabe energy and it definitely rings through all of the songs he has written and performed with this band. The guy is just a prick and a self-victimizing asshole.
I think he’s the primary reason FFDP is mocked so badly.
In case anyone doesn’t know, he tried to murder his (now ex) wife. As in, towel stuffed down her throat, his hands around her neck, and screaming, “I’ll kill you,” when the cops got there. And someone dropped the charges, for some fucking reason.