The handshake is something we've been doing for a long time, with one theory of it's origin having to do with showing strangers you aren't holding a weapon. Regardless of how shaking hands become a common way to meet, say goodbye or congratulating someone, I think we've all experienced the dreaded "too long handshake".

When someone continues to shake and grip your hand, long after you feel the time is up, it makes us uncomfortable. In a new study, researchers at the University of Dundee concluded that participants showed less "interactional" enjoyment after a longer handshake, laughing less and showing increased anxiety. In other words, long hand shakes are simply uncomfortable.

So how long should the ideal handshake last? No longer than three seconds. You know who is really bad at really long handshaking? Politicians. Trump has been routinely  timed shaking hands for up to 19 seconds. One time he shook French president Emmanuel Macrons hand for 29 seconds. Just let it go, man.