Pleasure and pain are the pair that decides virtually everything we do and don't do. If you do a thing, it's because you associate more pleasure than pain with it. If you don't do a thing, it's because you associate more pain than pleasure with it.
If you have a bad habit you want to get rid of but cannot (say, smoking), it's because the pain you associate with quitting smoking is larger than the pleasure you associate with the results of quitting smoking.
Associating more pain with “not quitting smoking” and more pleasure with the results helps you get rid of the habit.
Do you procrastinate? That's because you associate more pain with doing something. Even though you know once you finish it, you will be happy, but the pain associated with doing it now overweighs the pleasure associated with finishing it. Solution? Associate massive pain with not doing it now.