It's actually common for workers to pass each other in the halls each afternoon and stop and think if they've shaken hands yet that day. So, they shake just to be sure. In a social setting, things get a little more complex. Men generally kiss when introduced to women unless the woman is much older, in which case a handshake is in order. And men just shake hands when introduced to other men, unless it's New Years or their birthday or a very close friend, in which case a kiss is in order.
Women have it a bit easier.
They basically get to kiss everyone, except younger men. For those who do kiss, there's a strict kissing protocol, but no one will ever tell you what it is. So, you're left trying to follow the other air-kissers lead. The number of air kisses varies by region. In the south, they air kiss three times.