Facebook Silence
When you accept a friend request just to make it look like you're not going to ignore them forever. You're like, 'Okay, I'm friends with them now. I can leave them in the dark.'
You accept a friend request from your old nemesis just to make them think you're not ignoring them on purpose.
You add your teacher on Facebook just to look like you're not avoiding them. You're not. You're just being a student.
You accept a friend request from your ex just to make them think you're still interested. You're not. You're just confused.