Depends on what kind of match I'm playing and whom I'm playing against.
Ladder match - I'm polite but intense. I will acknowledge good shots and say thanks, but only till after the match is done will I become chatty. Unless I'm getting my butt kicked, then the jokes come out.
I'm in this social doubles thing every week, we all know each other so I'm very comfortable in this setting, so I'm a total clown. It's competitive but very fun, so I'm pretty loud.....lots of Ric Flair "WOOO!!!", "Daaamn!!", etc....
It's set to loud club music, so I'm frequently doing some silly dance moves a la moonwalking or Gangnam style stuff. Silly basically. Good way to let off some steam. Regulars get a kick out of my antics while the new people think I'm on crack.