This may sound weird but my biggest "FFUU" moment was in Mine Craft. I had just built my fortress up and had a bunch of swords and bows and arrows and intended to go hunt some Creepers to make a bunch of TNT. So I decide to take it easy by going to "easy" mode and the within the first minute of exploring, I get surrounded by 3 skeleton archers, 4 creepers, 2 spiders, and a zombie. I lost all of my stuff and got sent back to my respwan point and figure that I would just go and retrieve my things again but they were gone. So, angrily, I went back to my house and got killed again by 2 creepers who were in my base due to the door being opened. Later found out that I was on top of 2 monster spawners which explains where all those enemies came from. To say the least, I was pissed.