I’ve just gotten used to sneezing in my sleeve. And now it’s time to let the handshake meet an end : With everything we now know about germs, about the ferocity with which trouble travels via hand-to-hand contact, why do we feel obligated to soldier on with this centuries-old tradition? It’s not clear exactly why and when the handshake became our default in-person greeting. The most common explanation is that it was how a man, upon meeting another, could establish that neither was carrying a weapon.