Every person needs sleep everyday. But with the high development of society, most people have more and more things to do and have less time to sleep. As a result, many people are lack of sleep. For a short time, they may not realize the bad side of it, but it will bring something bad for them after a long term. First of all, lack of sleep will do harm to people’s look. If they do not sleep enough, they will get black eyes and bad skin easily, which will make people look no so beautiful. Secondly, lack of sleep is bad for the spiritual outlook. A person who lacking of sleep always looks tired and has no power to do things. Last, not enough sleep for a long time will have bad influence of thought. They always can’t be active in mind.