I've hated Paul Reiser for about 2 decades now. I can't really put my finger on what I hate so much about him. I've seen his shows and comedy routines on tv, and they were okay; nothing really hateable. I can't figure it out. I just hate him. It's possibly based on his looks, more specifically his hair. Maybe.
I know it's wrong to hate people, especially when there's no real reason to hate them, but if I were stranded on the side of the road and he came along and fixed my car and gave me some money, I'd still hate him.
Also when I tell people I hate him, they usually say, "You know, I've never really thought about it before, but now that you mention it, I believe I hate Paul Reiser too."