When your friends on league say they will play the next match, then they unfriend you quickly.

http://www.quickmeme.com/img/3a/3a053e9b1072935c49a08fc3f5ef8ffe68bbfb9c8013a88e63649617c1f012fb.jpg (Thankfully this only happened to me one time in my whole time playing this game, he was a rengar main.)