People who mine from a rock even/especially when it's obvious someone else is mining that rock. Admittedly, I have an addy pickaxe so that doesn't happen as much anymore, but when mining coal it can be a real pain. What, like your rune pickaxe gives you the right to be a jerk? The ability, yes, but not the right. For me, ninja miners outweigh the 'evil score' of scammers, n00bs, and dirty PKers by 100%.