Nobody controls their dreams... they are by nature part of the subconcience.

Or do you mean that you dream you can control your dreams?

A lucid dream is one is which you are aware you are dreaming. In this kind of dream many people are able to exert some control over what is happening. It is also a skill than can be learned and practised. I'm not sure what it 'means' exactly, it is just a skill that some people have naturally and others can learn.

Do some research on dream control or lucid dreaming if you want to learn more.

ERROR: You must spread some Reputation around before giving it to QLP again.

I do this quite frequently since I live in a land of chaos, but it takes years to learn how to accomplish this.

I can control my dreams, most of them anyway, especially nightmares, to teach yourself how to wake up when you know your having a nightmare, say to yourself every night before going to sleep "its only a dream" , say this to yourself 10 times before sleep every night and eventually when you have a nightmare you will automatically say it to yourself in your dream "its only a dream" and you will wake up :) try it :) I've done this for many years and it always works :)

This is how I spend most of my time

The mind lets you feel you are in control, but that state is not associated with REM sleep where real dreaming occurs.

Jared Lee Loughner, the AZ shooter, is fascinated by lucid dreaming and claims he can turn off his alarm clock when he sleepwalks.

http://en.wikipedia.org/wiki/Sleep_paralysis

Read this and see if it may explain anything.