The handshake has been a standard part of social etiquette for millennia. At the Acropolis Museum in Athens, there's a bas-relief of Hera, the queen of the gods, shaking hands with Athena, the goddess of wisdom—which is apt, because the handshake is generally a wise move. One of the most plausible origin theories is that the handshake was a way to show you held no weapon in your hand. As such, it's something of a universal gesture of peace.

These days, it's an accepted part of sports ritual everywhere from Little League baseball...