This edges very close to an affective death spiral,

Agreed. I find that often it isn't so much that I find the thought process intrinsically pleasurable (affective), but that in thinking about it too much, I over-stimulate the trace of the argument so that after a while I can't recall the subtleties and can't locate the support. After about 7 comments back and forth, I feel like a champion for a cause (no objective values RESULTS IN NIHILISM!!) that I can't relate to anymore. Then I need to step back and not care about it for a while, and maybe the cause will spontaneously generate again, or perhaps I'll have learned enough weighting in another direction that the cause never takes off again.