Have fun in Israel, but be smart. Tour directors take a dim view of misbehavior of any kind and the quickest way home from Israel is to be kicked off your trip -- and it does happen.

Don't even think of using illegal drugs in Israel. If you do, don't expect your American citizenship to get you out of trouble if you're caught.  Before going to Israel, rent the film Midnight Express. Israeli prisons aren't anything like the Turkish one in the film, but you'll get the point that getting high isn't worth the risk of getting caught.