Do dreams always happen?

Does a person dream every night they sleep or are there times when your brain just doesn't bother with or forgets to make a dream or something.
I have wondered this for a long time, and this is the perfect place to ask! I read the homepage introductions and don't remember seeing it there, but if it is already on this site somewhere please leave a link.:)

You have several dreams while you sleep,buts its extremely easy to forget them when you wake up.The most vivid ones are the ones you have while in REM.