1. Mood. Many people believe that if they want to do certain things then they have to be in correct mood. If you have to perform certain task which you think is not pleasant then you won't be in correct mood. For example if the task is to wash clothes or tidy your room, you won't get the correct mood for days. But once you forget the mood and started performing that task, it will be finished in no time. It is also observed that more 'dirty' the task is quicker you will finish it.
2. Wrong estimation of time. It is usual that our estimate of particular task often proves wrong. We think that X task will take say 10 hours of work, but when you start the work it seems to take longer then what you anticipated. At this point people get discouraged and think that they will never complete the X task. Sometime the same problem reverses, for example if you think that you will complete the X task in very short time then you start thinking that you have lots of time to do it, why hurry. With this type of thinking you will end up doing nothing. Like your leaving room is in a mesh, since you think that you can tidying up your leaving room in minutes.
3. Fear. This is most important psychological barrier which prevents people to do things. When you have to perform certain task which gives you some monetary benefits then the fear of failure is the main reason to procrastinate. People can not stand the failure, let alone the thought of it.
Now you know some of the important reasons for procrastination. But what will be the solution? Is there any way out? Certainly, but you have to do some serious effort. If you think that there is some magical formula to stop procrastination then you are wrong. There is no such magic formula. You have to erase some of your habits and start all over again. If you are wondering whether it is possible, then let me assure you that it is quite possible to stop procrastination