What is procrastination?

Is it the art of avoiding something that you know that you should be doing? Is it another word for doing other things that are important to you, rather than work on the thing you procrastinate from doing? Is it a good thing, or a very bad thing?

Wikipedia says:

".....Procrastination refers to the deferment of actions or tasks to a later time. Psychologists often cite this human behavior as a mechanism for coping with the anxiety associated with starting and/or completing any task or decision....."

Princeton defines a procrastinator as "... someone who postpones work (especially out of laziness or habitual carelessness)..."

I'm not sure that carelessness or laziness can truly be used as a wide spread generalization of the reason for procrastination, since a lot of my procrastination seems to be in the terms of "I have to do that instead..." and that always is something that is harder to do. So, I think the anxiety associated with completing a task is just as valid as any level of perceived laziness.

I realized a few days ago, in one of those moments of epiphany, that the reason I never finish my stories is because I had promise myself once, years and years ago, that my dad would get to read my first published book before he passes away. On some level, I think I have this fear of getting published because of that vaguely remembered thought years ago.