I will not disqualify Beavis and Butthead. Thing is, punching them in the face wouldn't do any good--you'd just have a sore hand, and they'd be that much more stupid.
+1 for Gul Dukat. I remember when he killed Jadzia Dax, and stood over her and said he never meant her any harm. "LIAR!" I hissed at the screen. "You'd burn down the galaxy to get what you wanted!"
Negan, from The Walking Dead. I had my own name for the character--Schicklgruber. (Yeah, I went there. Tell me I'm wrong. If you can.) It angers me that both the comic and the TV series try to redeem him. I fail to see the point that Kirkman and the showrunners are trying to make.
Ed Cocannon, from the movie The Verdict. Would stoop to any level to win his case--even employing a woman to begin a relationship with the plaintiff's attorney (Paul Newman's character.)