A leaky roof.
Seriously Roof? You've only got one job and you suck at it?! I would understand if you were a combination roof/floor/wall; you wouldn't know what to protect from what. I would totally dig that; choices are tough. But serious, roof - you stop things from the sky from getting through you. You are like my sky bouncer: hot girls, yes; rain/dudes, no. I understand if you can't stop asteroids or friggen tree branches - but rain, come on. I treat you right! New shingles and good support; but in return, stop the dang rain!
Leaky roof, you suck!