I once read, don't remember where, something about one of the main differences between japanese and occidental/christian cultures being what their morals are based on: shame the former, guilt the second. Both deal with breaking a prescriptive/nomic code and being more or less ostracized as a consequence; but, whereas in shame the fault is acknowledged publicly and publicly as well is expected to be mend (and thus the conflict to disappear), in guilt the fault is acknowledged intimately (in solitude) and it's MEANT TO STAY, no matter what; i.e. it is the very fact that you'll never, ever, forget and get yourself forgiven for what you did, what allows you to function properly within a guilty society.
So: immense shame? sometimes, yeah, and I hate it; guilt? always; it's like a background noise; it's necessary. Guilt can be an overwhelmingly powerful drive to live, to go on, as you haven't finished yet paying for that shit you did, and thus your entire life is not just molded but actually preserved/founded by fault.