There are two main ways to handshake someone. You either do the normal one or you fistbump them. Fistbump looks like a rock, normal handshakes look like paper. When you see people about to fistbump you, say "paper covers rock" and then say you're just kidding and go in for another handshake, but when they put their hand out say "scissors beats paper", and you just forced someone to lose two rock paper scissors games, and then you tell them to do the same thing to everyone they handshake. And eventually everyone in the world will only be able to greet each other through rock paper scissors battles.