I have lost 2 racquets in my earlier tennis years
because they slipped out of my hand and got smashed
onto ground( thank god they didn't fly to other players..)
while serving. I don't do that any more and I don't know why.
I think my grip firms up unconsciusly while/after I hit serves...
"I mean, you have to get emotionally involved. Otherwise, you're doing the wrong thing, you have the wrong job." - Wilander, after French Open 2008