I wish fish were twice as fast as sharks.

Two wishes. There Can Be Only One. Both of you fight to the death. Both of you dies.

I wish you both weren't dead.

We both revive... as humans.
I wish eragon was half-fish.

Eragon's right side is now fish, and his left is human.

I wish Asssprite would build his world already!

My world is completed, but hidden away from your sight.
I wish my world had fish in it.

Asssprite wrote:

I wish fish were twice as fast as sharks.

I am now an Eldritch Abomination. Time to play with reality.

Asssprite wrote:

I wish fish were twice half as fast as sharks.

Your world has fish in it but they're all dead.

I wish eragon would stop screwing with reality we need that.

He stops screwing with reality, only for W!tch to take over the multiverse!

I wish Asssprite's world would have more biodiversity.

My world has sixty thousand individual species of leeches.
I wish fish could eat leeches.

They do, this is somehow bad for the economy

I wish for nachos

You get a wax sculpture of nachos.

I wish the cockroach in my hall way would go away.

It leaves your hallway. It takes up residence in your bedroom.
I wish fish could sing. Better yet, I wish they could rap.

They sing. They rap. Somehow this is bad for the economy.

I wish I would go to sleep already!

You can sleep, but only in other peoples bedrooms.
I wish fish had a positive effect on the economy.

They do, they rule it.

I wish to I could rewrite reality again.

You can. Somehow, this is bad for the economy of the multiverse. Probably because you are not trained in Multiversal Economics.

I wish the bedroom I end up sleeping in belongs to a clean, nice and understanding person who respects my personal privacy and does not question why I am there.

You wake up in an extremely clean bathtub full of ice with your kidneys out and an apology note taped to the mirror.
I wish fish flew instead of swimming, but only in australia.

(what happened to the "nice" part of my wish?!)

Fish now fly. All fish do. Including the occasional science-shark.

I wish someone will sing I'll Make A Man Out Of You with me.

(They were very kind and reasonable up until they took out your organs, and they left an apology. Besides, I hear they baked cookies for the people who bought your bits.)
Someone does. They then proceed to make a man out of you, if you know what I mean.
I wish fish could grant wishes.

They do but only about fish related things.

I wish I could own a planet entirely populated with cats.

You own the planet, but cannot go there. The cats, being cats, disregard you, as each one of them is convinced that they own the planet and more besides.
I wish that your cat planet had fish so they would stop having to resort to cannibalism.

My cat planet has fish but they still eat each other and not the fish.

I wish for my cat planet to go to war with Asssprite's planet.

They declare war on each other. However, they are many light years away from each other, and neither of them has the tools required to build even rudimentary spaceships.
I wish for a longer weekend.

You get a longer week end but the only thing it changes is the names of the days to all being Saturday and Sunday. You still have to do all of your weekday responsibilities.

I wish for cat planet to become cat scientist planet.

They are only interested in social sciences.
I wish I had no responsibilities but full privileges.