Granted, but all of your food has to be the same color without added dye; choose a color, and it stays that way for the rest of your life. I wish to be a metamorphagus (think Tonks).
Granted... but then a cat shows up...
I wish I could have any super powers I could imagine.
Granted, but you attend Hogwarts the same year as the Final Battle in book seven, and you die before the school year is over.
I wish that I didn't have OCD.
Granted, but you become a hoarder instead
I wish I was able to teleport through the summer and get back to school
Granted, but every class you have is on the exact same subject, which also happens to be your least favorite taught be your least favorite teacher.
I wish all my college debt was suddenly cleared so that I owed nothing.