Anyway, I came across this video a while back, posted by Stefan Molyneux in 2008. I don't agree with all of his ideas, but his views on procrastination make a lot of sense. If you struggle with procrastination, I honestly think the concepts he discusses here could set you on the right path.
Over the past few years I've developed a number of systems that work for me, mostly through experimentation and reading a handful of the better personal development books out there, but I've never heard someone describe the underlying cause for procrastination in such an eloquent, palatable way.
Note that this video runs a bit long, around 30 minutes or so. If you don't have time now, I highly recommend bookmarking it for later.