I suppose with me it's desire/willpower, but not quite in the ways above -- basically, despite being educated and competent, I do not enjoy the act of writing programs at all. Scripts I can cope with because if you've got to do manual labour anyway, it's easier to write a script to do it than to program, but I really dislike any programming task -- big, small, work, hobby. As for why that is, I expect it's a combination of being forced (the only useful languages I know were taught to me at university) and getting bored very, very easily with projects. Even small web-based projects which I start full of enthusiasm I abandon quickly, because I'm a designer and project manager, not a coder.

In summary I guess what I want to say is this: just because one self-identifies as a computer science geek -- and has paper qualifications showing a great deal of schooling in computer science -- does not make one a programmer. In fact, it doesn't imply one enjoys programming at all. That's exactly the problem I ran into when trying to find a graduate job, and a sizeable part of the motivation behind my continuing on to a PhD...