The AI director on Left 4 Dead 2.
I was running a normal single player campaign on Swamp Fever, trying to earn some achievements by only using a melee weapon and letting the AI handle the guns. Big mistake.
The AI gets completely wiped out on a gauntlet event in which you have to wait for a ferry to slowly come across to you, fighting off waves of infected until it arrives. I stagger onto the boat with all the other characters dead, and heal up. As I'm crossing, 2 of the characters respawn in a shed on the other side, so I let them out. All they have is pistols. All I have is a fire axe. We have no healing items, and both of the AI are at 50% health, myself at 80%.
And then the AI director decides its time for a tank. A tank verses a man with an axe and two crippled retards who have pistols (If you havn't played the game with the AI, you have no idea just how retarded it can be).
To be fair, we did win, barely. Carried on, rescued the fourth person, all was going well, until the next gauntlet event, an alarm which summons infected when you open a door. That was when things got frustrating, because after all my shitty luck at the start of the campaign, I get pounced on by a hunter and the three retards who are accompanying me literally just stand next to me, shooting common infected, as I get mauled to death. Now, this is normal mode, so it took a good 15 seconds for the thing to kill me. 15 seconds in which the AI just stood there and ignored the screaming, bleeding con-man lying on the floor.
Motherfuckers.