You can but they have the nasty habit of unraveling with in a week.

I wish being a NarniaWeb moderator was a paying job.

Voila! Being a moderator does become a paying job. But then you have to pay tax and satisfy performance criteria after which it stops being a fun leisure time pursuit.

I wish I didn't get asthma.

You don't get asthma, you get pneumonia instead.

I wish I was taller ...

You get so tall you can't walk through any doors, and when you are inside buildings you always have to bend over so your back hurts all the time!

I wish I had red hair...

you can, but it won't match any of your clothes

I wish I could swim

Granted, but now you're a great white shark and will miss all your human friends.

I wish I were a published writer.

You are, but all your books are technical books on some obscure detail in your work, and only a small circle of people read them.

I wish I could live in London for a year.

You live in London for a year, and then crash on the way back home.

I wish the Wii U was out already.

The Wii U comes out early, but it glitches all the time and generally has so many bugs that you can't play with it.

I wish I was done with all my work.

You finish all your work on this earth, then are unfulfilled and turn to a life of drunken gluttony.

I wish the dragons had a ghost of a chance of winning this tournament.

Granted! The Ghost of a Chance begins haunting your castle by the sea. (in the nicest way possible)

I wish I could catch up on lost sleep.

You catch up on lost sleep but you don't wake up for a year!

I wish I was a super hero.

You gain the super power of passing through solid objects! However, you can't control it...

I wish I could have a banana tree that grows super-yummy bananas.

You get a banana tree that grows super-yummy bananas, but then you turn into a human, who doesn't like bananas!

I wish I could have a pet bunny!

You have a pet bunny with a deep and abiding love for hiding in fuzzy slippers and nibbling toes.

I wish I could control the weather.