I used to do it all the time way back when, now I just play it out (if I'm that annoyed at the performance on the first ball I just turn the game off and go do something else). Sometimes you get so pissed off at the first ball that it puts pressure on to play better.
Mostly it came out of starting to play in tournaments though, because if you do a restart you get a zero (not that I haven't seen some top players 'sneak' a restart in, there are a couple of cheaters out there).
I started to record all my scores on my games and keep it in a spreadsheet for a couple of reasons; one, to see if I'm *really* playing that title enough to justify keeping it, and two, to see if I'm actually getting better over the years. If I throw out 2/3's of games by restarting and not recording that score, how would I know if I'm getting better or not?
It helps to not restart on some games that are really short players anyway because you're going to lose maybe a minute before you restart? Sometimes I'll have 10 minutes to play Stars or Mystic and play 20 games in that time!