are people with bipolar dangerous

What does it mean when people say that a person has bipolar disorder?
I've heard this so many times, but what is and is somehow dangerous?
Okay, why do not we turn to copy and paste the answers from the websites and give you a shot of this principle and explain it in plain English. A bipolar disorder is basically have a good side and evil on a person and pull and tear at each other. A minute can be happy and smiling, and a few minutes later she is morose and depressed and angry with the world. One moment you can be happy with one person and the next time you're angry with them. Part of you is pulling to be a happy person and on the other side of you is saying no, I'm moody and mad and not want to be happy. It's almost like having two different personalities. The person has mood swings which are often severe uncontrollable and go from one extreme to another.
Living with Bipolar Disorder