I saw someone mention GM's and cheating, so I figured I'd add my $0.02. A GM can not cheat. GM's are the god at your table and they can do what they want. I almost always roll behind the screen and if I think a miss would have been a hit, it will be. Especially if I need to knock a player off of their high horse. To me this is no different that adding the advanced template to creatures.
OLD SKOOL! (Yes, the "K" is correct.)
I've found a healthy flogging of players before the game starts goes a long way towards a good game, as well.
Just make sure the nails are extra-rusty.
(And if you're not at least occasionally kicking them in the crotch, can you really be sure they're enjoying the rest of the game, when they're not being kicked in the crotch?)