where do you stand on people who don't friend you back?

I decided a long time ago that what I wanted out of LJ was relationships, and not just to be some kind of fan club, so for the most part, I defriend if someone has not friended me back in a certain amount of time. There are always exceptions...for example, I'm friended to someone who is a TV writer, I just read her LJ for the insights and don't expect her to friend me back. And yes, it does kind of offend me when someone with whom I have lots of mutual friends won't friend back! ;)