The level in payday 2 where you have to rob the server from the fbi. It's extremely hard as it is but in order to do it perfectly without setting off any alarms you need extreme luck.
You've got a 10% chance of cutting the right fuse boxes and even if you do its extremely difficult to pull off the rest of the mission without alerting an enemy.
Took me 2 days and 16 hours to do it.