The worst are lucid dreams... I used to get them a lot in the past but hardly get them now. The only problem is now I experience sleep paralysis. If you are not aware of what that is.. it's when your mind wakes up but your body doesn't, meaning: you are trying to open your eyes (sometimes they can be) or move a leg because you know that you are awake but can't do anything about it. I've tried screaming and everything, but your body doesn't know that you are awake yet. It is the scariest thing that I have ever experienced in my life. I have only had it for 1 minute tops but some people will get it for a half hour. If you have never gone threw this, count your blessings.