Playing as aggro freeze mage vs deathrattle rogue. Have him at 10 and he's just put me at 1 and popped my first Ice Block. I've got 7 mana with Fireball, Forgotten Torch, Coldlight Oracle, Ice Block, Arcane Missles, Ice Lance. Drop 2nd Ice Block and Coldlight Oracle. Draw another Arcane Missles and Mana Wyrm (or something else useless). He's got 6 minions on board.
So sitting there with 1 mana debating between Arcane Missles hoping to hit face once and guarantee win next turn, or Ice Lance and give myself the win if I draw Frostbolt (I believe there were still 2 in deck, can't remember how many cards I had left but had played Coldlight and at least one AI) or 2nd Ice Lance.
I (wrongly, I believe) decide to go for Arcane Missles. Hit Leper Gnome, lose game. Lesson learned