Cracks me up every time...
I understand how Scissors can beat Paper, and I get how a Rock can beat Scissors, but how the hell does Paper can beat Rock? Is Paper supposed to magically wrap around Rock and render it immobile or something? Then why can't Paper also do this to Scissors? Hell, screw Scissors; why can't Paper do this to people? Why aren't sheets of college ruled notebook Paper constantly suffocating students as they take notes in class? I'll tell you why: because Paper can't beat anybody. Paper sucks - a Rock would tear that shit up in 2 seconds flat.
When I play Rock-Paper-Scissors, I always choose Rock. Then when somebody claims to have "beaten" me with their Paper, I can punch them in the face with my already-balled-up fist and say, "Oh jeez! I'm sorry... I thought your Paper would protect you, you jackass."