Make a Wish. Have it horribly corrupted.

[Dracon]

I wish people would remember to make a wish.

[Hicky]

Granted, but the wishes are paradoxical.

I wish for a long tongue.

[master1]

Granted. *a disembodied tongue appears before you*

I wish I didn't sweat.

[progartpkmn98]

Granted. Now you're pores are clogged, thus making you have acne everywhere .

I wish for peace on Earth. And ALL of the Earth.

[Webby2]

Granted. The earth is covered in pieces of cake.

I wish I wasn't hungry.

[Spriter Neb]

granted, but you will be eternally thirsty.

I wish HGSS were a American only game.

[master1]

Granted, but I'm British so I'm going to use my magic to send you to the moon out of spite. Rar!

I wish the moon really was made of cheese.

[Spook]

Granted.
It loses orbit and crashes into earth Killing people in a Cheesy Death.

....Hah.

I wish I could've expanded that 'Hah'

[Hicky]

Granted, but it involves you going on an an unrelated rant about cybernetics.

I wish there were more greeting words in English.

[Spook]

Granted, Now when people greet you they hit you in the face.

I wish I owned a Team of Obediant and Worthy Ghost pokemon.

[progartpkmn98]

Granted, but they die the moment you get them.

I wish for the Action Replay DSi to come out.

[Spriter Neb]

Granted, but your DSi explodes.

I wish that my crush was camping with me.

[Apprentice]

Granted, but then a similar experience to the book Hatchet occurs.

I wish I was Ken Jennings.

[Spriter Neb]

Granted, but then you wished you were The Rise of AppRAWRntice.

I wish I understood IVs

[Pichu!!]

Granted but then IV's were removed from the game, to be replaced with IAPXV's

I wish I could stay in Disneyland FOREVER.