I've done a variety of jobs, from classic intro-job retail to working in a computer tape library to scoring essays to teaching to, yes, actually, programming.

I've done a variety of jobs, from classic intro-job retail to working in a computer tape library to scoring essays to teaching to, yes, actually, programming. :-) In my experience, programming is perhaps the hardest of the lot to do consistently, all day, day in, day out. Some days I manage to really get into "hack mode" and crank out lots of good code. Other days I can barely focus and don't actually produce much. I really think a lot of it is the cubicle, etc., environment, as my days spent programming in an office were generally better than being in a cubicle. Either way, I had no problem working and staying on task while sorting computer tapes. But serious programming requires a particular state of mind and deep understanding of the problem at hand. The harder it is to achieve that each day, the harder it is to be productive as a programmer.