About the ouch! reflex: It took a lot of therapy to get to the point where I can fairly reliably realize that there's a me getting hurt instead of just identifying with the attacking voice.
As for guilt and depression, does anyone have information about how depression plays out in non-Christian cultures?
One other angle on culture: I think there's pressure in America to be busy, happy, and social all the time. This could add to depression, both by defining people who are don't fit the ideal as depressed, and by setting up people who are a little depressed to think they're deeply defective, which knocks them down farther.
I have a notion that people have a "that action sounds good or bad to me" slider in their minds. It's probably physiological. If the slider is stuck on the sounds bad side, you get the inert sort of depression. If it's stuck on the sounds good side, you get hypomania or mania.
Heading off into tentative hypothesis land, there might be two sliders, one for action, and the other for thought. If just the thought part is activated on the sounds bad side, then a lot in your head automatically seems bad to you, though you might be able to take reliable action. If the sounds good is too active, then you might get racing thoughts, hyperfocus, or obsessive-compulsive disorder.
Anyway, it's conceivable to me that depression is an overamplification of the necessary ability to choose not to do things.
 There are other sorts of depression. Some people have a strong sense of duty and do the useful stuff, but are miserable and possibly suicidal (see Good Mood by Julian Simon), some people can do the low effort pleasant things but not the useful things, and I think obsessing about how awful other people are rather than how awful you are is something like the depressive pattern, but probably less self-destructive, especially in the short run.