Facebook obligate friend
You get a friend request, you think about ignoring it, but you end up accepting it because you're a weak, confused, Facebook-obsessed mess.
My friend's mom sent me a friend request. I accepted it because I felt like I had to.
My friend's friend's dog sent me a friend request. I accepted it because I was too tired to say no.
My friend's friend's friend sent me a friend request. I accepted it because I was too confused to think straight.