1. Pikmin 2 - Submerged castle - "Ok this should be fun, only blue pikmin, fiery Blublax over there, yup this should be fun" *X amount of time later* "Hopefully this is the last treasure, I've been here a little too long" *Waterwraith* "OH GOD WHAT THE forget IS THAT, WHY IS IT CRUSHING MY PIKMIN!"
2. Any boss battle with a time limit - Do I need to explain this? Most timed boss fights end up being insanely difficult.
3. Super Mario Galaxy - Bouldergeist daredevil run - 1 HP in a boss fight that can take awhile, need I say more?
4. Psychonauts - Meat Circus level - Defend the brat trying to catch a bunny, outrun the rising water through a series of difficult platforming segments while your father throws flaming maces at you, and three boss fights.
5. Super Meat Boy - Everything