For those of you unfamiliar with South Park or 'Scott the Dick':
Scott The Dick is a character who first appeared in the Terence & Philip episode. He is every TV bad guy: He's arbitrarily nasty for no reason, and exists solely to make life difficult for the protagonists. He is an easy formula for lazy one dimensional villains.
The biggest Star Trek example of a 'Scott The Dick' is Brunt, but DS9 and some of the other Treks are rife with them, especially when it comes to single-appearance villains. Other recent examples are:
Jamm from Parks & Recreation
Eckley from CSI
What are some other big Scott the Dick characters in TV, and why do screenwriters fall back on them so easily? Is it just more economical to have one composite character for everybody who gets in the way of the characters getting what they want?