I started reading book 2 of a new series and gave up after a couple chapters. Book 1 was about the main character. Book 2 was building up the bad guys to set up an inevitable confrontation. I have discovered that most of the time I don't like reading about the bad guys.
A few years back while I was sampling new authors I found a book with a villain so vile that I quit reading immediately. I did not want to spend any time in that twisted person's mind. Nor did I want any description of the bloodbath he'd left behind. (shiver)
Maybe that's what makes first person books so popular - no foray into the mind of the antagonist?
Daniel Abraham's The Dagger and The Coin series has a wonderful antagonist who doesn't mean to be evil, he just makes really bad choices. I find that kind of bad guy fascinating. He's doing all the wrong things for the right reasons.
When an antagonist is over the top, I tend to skim those chapters, eager to get back to my favorite characters. It's a hard balance to create characters that are interesting and antithetical to one another. Too often authors cheat a little with a cardboard, cliche villain. I've been called on it a couple times by my beta readers (Thanks!). When I work a bit harder at figuring out who the bad guy is and what he really wants, it makes for a much better story.
But I don't like writing about them any more than reading about them. I tend to use the reaction of the characters I prefer, rather than the action of the antagonist.