"The Monkeys Paw" by W. W. Jacobs
You can make three wishes. You can ask for three things - anything in the world.
You can wish for the moon, the sun, the stars. How wonderful, you say.
But think about it for a minute. When your wish comes true, that is only the beginning. When you change one thing, then you change another, and another.
Perhaps you don't want these other changes, but how can you stop them?