Dreams can be disturbing but as JayUnit said, they're only dreams. They're not reality, and so many things can be projected into your dreams that just about anything can happen.
Some say they can control their dreams, but I've never been able to! It'd be kinda cool to be able to just say, ok I'm dreaming about this as you're falling asleep and then you do! But on the other hand I guess it would be like anything else in life where if you get everything you ask for it gets really boring. If every dream was a good dream then it wouldn't feel as good as when you only have the random really good one.
Also, I personally think therapists read a little too much into dreams. I do agree that dreams have the ability to "tell" you things or they can be ways your subconscious can tackle a problem in a different way and your conscious mind can then try to interpret it. But I don't think there's set definitions for certain dream topics meaning certain things. I think it's very personalized.