Your worst moment in gaming.

[Symphony]

Besides the freaking Shadow Temple at LoZ: Master Quest, the final instance in Dragon Age: Origins was simply frustrating.

It had hordes of darkspawn charging on you, but normally that wouldn't be a problem, except that because of the number of enemies charging, they decided to give them 1 HP only. That would be a nice thing IF IT DIDN'T TAKE 30 SECONDS TO HIT THEM. I just freaking saw my party members hitting the enemies for a long time until they managed to hit it. Not even the unmissable magic bolts would hurt them.
It would've been tolerable if they didn't stop you in the middle of the battle and make you command the members that are NOT on your party to defeat another horde. I had barely given any equipment to some of them (Stern had his default clothing on >_>) and had no healers. Just great.