> I seem to get this way more often in winter, so it seems like it could be something like Seasonal Affective Disorder (i.e. clinical depression), but I'm never depressed, just unable to convince myself to take any other path than the easiest one (e.g. fast food instead of home cooking, Short stories instead of novels, video games instead of hobby coding, organizing my computer rather than cleaning my house, etc.)
I would point out that things like SAD (and deficiencies in general like vitamin D) are not necessarily binary or even discrete states where you either suffer it or don't; you can have it in lesser or greater amounts. It's the diagnosis which is discrete - don't confuse the map with the territory.
I'll give you three guesses as to where I got the term "ego depletion" :)
If it was random or constant, I would agree that that would be simple akrasia—but it's time-modulated, having long periods where I'm willing to attempt high-activation-cost tasks with no particular mental effort, and then long periods where considering such things seems all but impossible. The down periods are greater in the low-sunlight days of the year, whereas a bright blue summer sky can almost be guaranteed to put me in a somewhat manic state. But that's just a correlation, and I might be suffering from some combination of placebo effect and confirmation bias there ("ooh, blue sky, those make me work" -> production of dopamine resulting from that thought -> ability to work.)
I would point out that things like SAD (and deficiencies in general like vitamin D) are not necessarily binary or even discrete states where you either suffer it or don't; you can have it in lesser or greater amounts. It's the diagnosis which is discrete - don't confuse the map with the territory.
Although I'm not sure SAD is your problem, you may just have general issues with 'akrasia'. You may find useful or enjoy some of the articles in http://lesswrong.com/tag/akrasia/ (such as http://lesswrong.com/lw/f1/beware_trivial_inconveniences/ or http://lesswrong.com/lw/fu/share_your_antiakrasia_tricks/ ).