"Procrastinators often follow exactly the wrong tack. They try to minimize their commitments, assuming that if they have only a few things to do, they will quit procrastinating and get them done. But this goes contrary to the basic nature of the procrastinator and destroys his most important source of motivation. The few tasks on his list will be by definition the most important, and the only way to avoid doing them will be to do nothing. This is a way to become a couch potato, not an effective human being."
--John Perry, Structured Procrastination

"The whole idea is to give yourself a whole lot of really really constructive things to do as a way to avoid the really real things you need to be doing. [..] So as long as you're gonna waste time you might as well have a big range of things you can go procrastinate with that actually are reasonably good things to do. [..] Just make sure you've got reasonably healthy things as a way to avoid the stuff you really don't wanna go do."
--David Allen, @ 43 Folders' Productive Talk Episode 1: Procrastination

This is why the weekly review is so essential: it makes you choose things consciously to procrastinate with.

See this post also: My Take on Procrastination.