Is it okay to pat your opponent on the back while they're thinking?

If you're just sort of a friendly reassuring person, is it okay to pat your opponent on the back several times throughout the game while they're thinking to bolster their confidence?

No.  You are not supposed to speak, make noise, touch, or otherwise distract your opponent.  Naturally you can bend the rules in many circumstances, such as with a friend or kids, etc, but in a "serious" game, even a friendly one, probably best not to do this unless you know the person really, really well.   Also, it could even be considered condesending.  Instead of touching the other player, the best thing to do is use THEIR time to look at the board.  Its as valuable as your own clock time.  If you need a break, quietly leave the area.

Thanks :-)

I suppose my next question is, if you pat a player on the back several times thoughout the game while they're concentrating, and they happen to reel back and slug you in the jaw at some point, is that acceptable?