It does. You don't notice because its in south america.... for 0.000000001 seconds

I wish I had a katana

Sticking out of your leg

I wish for it to temporarily rain popcorn into a bucket I am carrying

It does. But it also rains gallons of hot melted butter. You drown because the bucket overflows. And you are in a bathtub. Its to slippery to get out

I wish I had a Katana. 

(notice the period )

You have a Katana. You also have a bomb under your house, which you do not realise

I wish I never get ill

You never get well either

I wish I had a life supply of C4. (Its competely safe too)

Most people never need C4, therefore a life supply is a very small amount

I wish that I had a garden of sunflowers

Wish granted. Someone mows the garden down.

I wish I had a white fence. 

There are people impaled on it

I wish for a sculpture of Darth Vader

Wish granted. You have a sculpture of Darth Vader. It gets destroyed in an earthquake.

I wish to wish this wish

Paradox detected. Eliminating source…

I wish for everything to be the exact same and time to continue onward. (Note the period.)

Granted. Everything freezes. Its the exact same. Time goes forward. No one is there to notice.

I wish for pizza.

Inside your stomach.

I wish for Books to be free.

* thats where I wanted the pizza to go thank you *

There are several free books. Especially if you go to the right book stores. Wish wasted

I wish for AI to not take over the world in the future

All AI and machinery and all records of them are eliminated. Society crumbles and we all die of starvation.

I wish to be the smartest person in the world without having my appearence changed in any way or having my brain be affected by my knowledge

Everyone is really dumb.

i wish to be omnipotent.

 Wish granted. everyone else made the same wish. World War III starts.... and never ends  ¯\_(ツ)_/¯

I wish for no more the queen is dead memes

Granted. They now meme the king is living.

I wish for a wish.

Wishing for another wish resulted with you still having one wish. You used up the first wish getting another one.

I wish for my character to become lv20.

granted your character is now the most painful to play build in the world 

I wish to colonise the Americas

Granted. Your Frog Tribe colonized a tiny pond in America

I wish for The Elder Wand.