You shouldn't date someone you can't stand.
Steve and Willow have been seeing each other for almost a year, but Willow gets on Steve's nerves because he finds her sense of humor too self depreciating.
Steve wants to decide whether or not to stay in the relationship.
Steve breaks things off with Willow, citing that they are too different.
Steve continues to be with Willow because she's pretty.
Steve is now free to date someone he is more compatible with.
Steve remains miserable because Willow has a personality and style that just doesn't mix with his.