I wish for a Pocket Dimension of Infinity Possibilities.
In this dimension i have the power of a god and can alter it in anyway possible. Create universes, establish lifeforms and change the laws of physic.
I can enter the dimension by will and take everybody or anything with me in or out of the pocket dimension. Everything send into the Pocket Dimension from the real world can be altered and also leaves it altered. But elements, which are impossible to function in the real world, will fall apart (but nothing from the real world will die, they will just lose the impossible elements). Since the dimension follows my rules, times flows like i want it to (slow it down or speed it up).
With this Pocket Dimension i can create unbelievable adventures. Want to live in the world of Dragon Ball, Star Wars or anything else? Just create the fictive universe, let me lose my memory and power until "death" and let time flow extreme slowly.
I could also heal any ills, become rich through infinity resources and unbelievable technology, learn everything i want with no time pressure and alternate my self in any form (which is possible).
Why still have the real world around? So that i don't lose my humanity, get lost in infinity power (unlike Doctor Manhattan from Watchman) and have a scale through other people. Of course, i would keep it a secret and if i would ever become tried of it, i could just die.