Sometimes my mind takes me out of reality briefly, but that may be different than what you are talking about.. I can't say it's always very pleasant, but as long as it isn't too deep or convincing you can reassure yourself that it isn't real. It is however always interesting. Also, I constantly live in my brain, in the section where I can just be by myself and think whatever the hell I want to, which is always interesting. However it also takes time away from things that are "actually" important in life, so trust me I don't think you would want to live this way if you think you have a snowballs chance in hell with a functional life.