Be careful what you wish for!
There's an old game where one person makes a wish, and then the next person grants it in a malicious way, as if they were an evil genie.
Example:
1: I wish for a million bucks.
2: Granted! One million adult male deer stampede through your home.
The second person must then make their own wish.
I'll start:
I wish I could get this song out of my head.