Priests are the best/worst!
Used Thoughtsteal, which randomly gives me two cards from the opponent's deck. I get Alexstraza. I horde it the whole game, then late game I play it, immediately reducing his health from 30 to 15, and Power Word shield it, giving it ten health. He takes some damage, plays Alexstraza and Jarraxus on himself, and thinks he'll win next turn.
NOPE, I top deck draw Inner Fire (makes a card's attack equal to its health), play Divine Spirit (doubles the health of a card), and suddenly Alexstraza has 20(!) attack.
And I never even got a chance to use that Mind Control I got turn 3.
Hearthstone is really great you guys, everyone should try it when it hits open beta this month!