Facebook obligate friend
You see a friend request, you know you shouldn't accept it, but you do anyway because you're a spineless, brainless, Facebook-loving idiot.
My friend's friend sent me a friend request. I accepted it because I was too dumb to think it through.
My teacher's friend sent me a friend request. I accepted it because I wanted to look good in front of my teacher.
My dog's best friend sent me a friend request. I accepted it because I was high and I didn't care.