Granted, but will be immediately hired by an advertising company to announce products that will become irresistible to you and whose compulsive shopping eventually lead you to a complete financial and psychological collapse...

I wish to be a cat.

Granted, but you can begin with being a copycat. :p

Now that rain has fallen upon here last weekend, I wish that rain would fall everytime I feel the weather is hot and while I'm not on the way.

Granted, but now you've heat all the time, therefore the rain falls continuously, and the water level is rising up to your floor. Hope you have a canoe at home...

I wish the people stop talking loudly in the public libraries.

Granted but now they're stood just outside the public libraries, shouting very loudly through megaphones about freedom of speech.

I wish I had a great idea for a new invention that would make millions

Granted, but someone implemented your idea a day before you did. Now you're broke and doomed to watch as another person becomes rich, famous and universally acclaimed and think that could have been you...

I wish to be able to see in complete darkness.

Granted, but now you are unable to see in any iluminated area.

I wish to be able to breath in water without losing the abilities to breath in air and walk in land.

Granted, but you get a nasty lung disease from breathing water, which is even more polluted than air.

I wish for enough time to play through my GOG backlog.

Granted. You are now unemployed.

I wish I could have a turkey sandwich ..

Granted, but you have a sandwich but no turkey. You have to find one first, or you'll have to resort to McD.

I wish that all nuclear warheads in the world would turn into plastics.

Granted, but now the plastics are going to pile up in that new landfill some politician somewhere just had to have. The rest will go in fresh water sources, causing sea life and aquatic birds to suffer.

I wish I had an extra $500...

Edit: I added my wish

Granted - Now all the mucus in your nose evaporated resulting in nose bleeds at awkward moments!

I wish I could travel into a sword and sorcery universe..

Granted, but you don't know where such a universe is located and nobody here can help you about it. Perhaps some games may have some clue...

I wish I could transfer loads of fat in my body to someone else's.

Granted, but the fat is returned... with interest rates of 500 percent.

I wish to be able of gifting GOG games at will (therefore, to have money to pay them).

Granted, but you have no will. :D

I wish to be able to make all new threads in a day to be all giveaways and new threads fill at least one full page of "General Discussion" in GOG forums.