Not every show has them and some shows use them to great effect, but don't overuse them. On the same token, sometimes, they get to be too much in general. For example, take the "heroes think they won but really they just did exactly what the antagonist wanted all along" cliche/trope.

This isn't a sitcom, but I'd say that Ben Linus from "Lost" qualifies. At some point it seems like the writers just decided he was always going to get the upper hand, was always one step ahead of everyone else, etc.

He was a very interesting character but ultimately his role got WAY too big for the purposes of the show, IMO.

Barney Stinson in HIMYM...the main reason why I can't watch that show!

Mr. Gold/Rumplestilskin in Once Upon a Time.

Barnfather and Gaffney from Homicide: Life on the Street. I stopped to watch the show because of them.
Nelle Porter on Ally McBeal sometimes was too much to bear.