I swear we used to have a thread like this (if I remember rightly, I started it, but it doesn't appear under threads I've started), but lots of searching and even trawling through 40 pages (yes, 40) of threads couldn't locate it.
So I figured I'd just start a new one. Grant the wish of the person posting above you but twist it so much that they wish they'd never wished for it.
Then make a wish yourself.
Person 1: I wish for a Ferrari.
Person 2: Granted. You smash your Ferrari into a wall and end up in a full-body cast.
I'll start. I wish it wasn't so fucking cold in my house.