Funny you mention that -- two days ago I started working on a new project, and I managed to get an almost ideal "non-work" feeling about it. I haven't been this productive and I haven't enjoyed work so much in quite a while. Right now it's Friday night in my time zone, and I'm frankly having more fun working than if I were somewhere out boozing.

The project however is not especially cool or interesting in any way. For me, the actual content of the work is much less important than the feeling that I'm getting good money for it, and even more importantly, that seeing the eventual results will give me the feeling of useful accomplishment. Either of these two can be enough to make me apply myself with genuine joy and enthusiasm to even the hardest toil, whether physical or intellectual. In contrast, what absolutely kills my enthusiasm and pushes me into severe akrasia is the feeling that the work I'm forced to do is ultimately without real value and useful purpose.

Another potentially significant factor are the co-workers I'm stuck with. Having to work with people whose company irritates or depresses me can make otherwise OK work feel awful, and this actually spills over into those parts of the work where they're not even present. Conversely, fun and likable co-workers can make even the worst drudgery enjoyable.