To put it simply, you find a way to corrupt the above poster's wish and give them hell, then put in your own wish for someone to fiddle with.
PosterA: I wish I was rich.
PosterB: You become to the richest person in the world, but you get mugged and swept of all your money as you walk out of the bank.
I wish I could fly.
...Something like that. Hopefully, you all have better imaginations than I do when it comes to making up examples. So, here we go.
I wish I could travel through time.