You know, I rarely get surges of any good emotion when I'm immersed in something. Frustration, annoyance, stress, etc, yes, but not joy or whatever. It's after I'm done and I look back at it and say "Was it worth that?" and the answer's yes that it all falls together. Release of endorphins, perhaps.

Sometimes there's those moment when you're sketching or painting and every line is just right but those are few and far between and you can't make yourself have them.