I have Rage Quit before.  When someone really trounces me, I'm mad more at myself than them, and abruptly quit to punish myself for playing so badly.  :)  I can usually play 3, 4, and 5 ends at a sitting, but I hate committing to any number of set ends, because it's just a game, and I have a life.  Very often I have to walk away from the pc for something, then forget to come back.

Set the ends to be played!!! I play between 4-8 ends always because I set it up.

I had a guy try to leave after the 3rd end of an 8 end game. He was up 3-1, left, so I won 12-3. Hopefully he learned a lesson. Hopefully you do too.