These have all happened to me and each one is as annoying as the other.

1: Wood mansion getting struck by lighting while you are getting wood. The fire spreads to the forest. Crap.

2:You built an awesome lava disposal and a creeper blows it up. The lava burns down your palace.

3:You go to your apocalypse base but a creeper activates the self destruct.

4:You are setting up a TNT cannon on your roof and it backfires.

5:Your fireplace sets fire to your mansion even though you had a brick chimney.

6:A server gets rolled back and you have to remake your mansion. Given by Fauxiss

7:A griefer destroys your house with TNT or lava. After raiding your chests. While you are getting wood to make your mansion. Given by Seemmetor

8:You have the volcano mod installed and one spawns in the middle of your mansion, spewing lava all over your estate.

9: You finally finish your mansion on multiplayer but the admin trolls you and changes your mansion into TNT. Your non destructive fireplace sets fire to the TNT. Trolol. TheBritishDiamond gave me the idea

10: You have tornado mod and a Level 5 Tornado curves into your house throwing lava from your hot tub everywhere. Seemmetor gave me the idea

11: Same as number 9 only you have redstone powering your redstone lamps. Idea given by Seemmetor.

Give a diamond or favorite if you like and add comments with what happened to you. I will update and add yours to the blog and give you credit. Thanks.