I read an interesting article about procrastination today. Some of it was bullshit, but I did agree with the claim that procrastination is irrational, that procrastinators are feeding their emotions.
Procrastinating Again? How to Kick the Habit: Scientific American
As for me, I most often procrastinate because I'm a perfectionist. If I'm not confident that I can complete a task to a level that satisfies me, I put it off. I've also procrastinated because of anxiety, to a lesser extent. For example, there have been times when I've known the balance in my bank account is pretty low, but I don't know the exact amount. Rather than checking my account balance, I put it off because I don't want to know. It's the feeling that seeing that number will actually cause pain.
I haven't found a solution to the anxiety, but for the perfectionism I can usually find some way to get myself to just start (there's too much variance for me to give a more detailed synopsis). At that point, it becomes an obsession until it's complete. As I write this, I find myself unable to start working on a presentation for a coil gun project that's due next week. I don't know where to start.