I get a lot of random request from people to be friends and I have split them into three categories: People that my other friends know, people I have never met and people I really don't want to be friends with. The last group is the one I am always troubled with. In all honesty Facebook isn't about friends so much, it's more about acquaintances. I've received a few request from people I work with or use to work with, sure I worked with them, but I would not call them friends. What do you do in that situation, I usually click the ignore button. If I don't really want to hang with you at work then why do I want you to know what I put on Facebook. I currently have 65 "friends," most are people I like to stay in contact with, old co workers, people from church and good friends. It almost feels like with some that if you even slightly know the person you need them to be a friend.
Maybe I'm old fashioned and have not fully assimilated to the concept. I do enjoy talking to people and knowing who they are without using email. Who knows, I'll continue to use it and I'll just continue to upset people.