Yep, every single time! I can't help it, Im terrible! I run through every single piece and add up the marks I would have given myself, then I think, perhaps I was too generous and take a few marks off, probably imagining mistakes that weren't even there.
Most of the time Ill have given myself 100 marks and when I get the result Ill have 124 marks or something so its a totally pointless exercise that just makes me worry until I get my result!