Everyone's just so strange

I'm currently at the beginning at season 3 and I am wondering why I'm even watching this show. I know I was originally attracted to it only because it's Peter Krause and Michael C. Hall, but seeing how well the show is rated I expected...more. I do like the Fisher brothers, but everyone else annoys the shit out of me.

I can't stand Claire with all her whining and drama. Ruth just rubs me the wrong way, and I think she's a little crazy. Rico, once he becomes partner, is now a huge asshole and feels entitled to everything; I mean, I understand not wanting to be treated like an employee anymore but most of the times it feels like he thinks he's now superior. Keith, who I thought was really nice at the beginning of the show, I now find to be an inconsiderate jerk.

I don't get what happened to Nate. He had a major surgery, and a year later he's married to Lisa?  I know she's the mother of his child, but she's also the mother of his child who wants him to never have anything to do with her. Their relationship is very strange and she's just plain weird. Also, Nate now seems to be a completely different person who's overly mellow and it annoys me.

I find almost everything about this show to be annoying, yet I can't stop watching. I can't figure out why...