Be careful what you wish for...

[Sleepy Ranger]

I wish Peter Jackson didn't kill Haldir and the Two Toweres movie.

Your wish is granted. Haldir survives but then he goes to Pellenor where he upstages Legolas at everything causing everyone to stare in awe and giving the Orcs and opening to kill everybody. But Haldir kills them all with his awesomeness but unfortunately all the Free People stop what they're doing to watch Haldir and in the end only Haldir survives.

I wish Sauron had a nagging wife.

[Shelob]

I wish I had an infinite supply of lembas.

Your wish is granted. Unfortunately your neatly stacked piles fall down one day, burying you forever.

I wish the Nazgul were afraid of the dark.

[Hookbill the Goomba]

I wish the Nazgul were afraid of the dark.

Abra-kadabra, foom a da lark! Nazgul now fear the dark! But they now spend their time hunting hobbits out to market, so they don't go out to market. And so starve to death, as do the Nazgul.

I wish Mount Doom had wheels.

[Glirdan]

Your wish is granted. Unfourtunately, it had no brakes and it ran over and killed you.

I wish the Ents would have done more in the War of the Ring.

[Sleepy Ranger]

I wish the Ents would have done more in the War of the Ring.

The ents decide to do more. They keep walking and walk onto you, squashing you flatter than a pancake. A random hobbit decides to eat your remains.

I wish Spiderman was the Ring Bearer.

[Hookbill the Goomba]

I wish Spiderman was the Ring Bearer.

Your wish is granted, but he is a missunderstood hero and is shot in the face by Elrond.

I wish Hobbits could fly.

[malkatoj]

I wish Hobbits could fly.

Your wish is granted. Hobbits can now fly. Out of pride for his newfound ability, Frodo attempts to fly to Mount Doom to destroy the ring. Legolas sees him when he gets to Mordor with his awesome elf vision, assumes he is something evil because nobody knows yet that hobbits can fly. Legolas shoots Frodo and the ring falls on an orc, who brings it to Sauron. Middle Earth has been destroyed.

I wish Merry and Pippin had created the rings.