Like any other person on this planet, I, too, am as imperfect or perfect. Perhaps, a little more "imperfect" than others, okay? :-) At the same time, when I am really guilty of something, I am one of the first to accept my guilt and to publicly owe up to it without much fuss. However, there is one area where I do not readily accept my guilt: it has to do with my somewhat imperfect driving and managing to get myself into sticky situations while doing so. I don't have the exact figures on my fingertips, but if the police were to count my instances of "rash" driving and "the ability to hit others' vehicles with mine, even if they be stationary and parked near the sides of the road", I would have had to surrender my driving licence long ago!
Having said that, usually, when I am guilty as hell of doing something wrong, I tend to sulk for hours, then retire to a quiet corner of my home and brood for some time, a packet of potato chips in my hand to see me through the down phase. I have learnt not to allow the brooding to take over my other, worldly, responsibilities. Hence, I always remember what is happening around me and what other tasks are still to be accomplished before the day is done. Feeling guilty is normal, but feeling depressed and shunning life's so many exciting events is not.
How soon would I go and express regrets to the wronged person? If the guilt is clear, I say "sorry" right away; if the guilt becomes clear later on, I make it a point to meet that person or call him up and convey my regrets. If my mistake hasn't been discovered, and the harm it caused was totally insignificant, I have sometimes cheated and not gone and owed up too. Which person hasn't cheated thus? I have felt somewhat more guilty for doing so ... but for just a few days. After that, these things are forgotten and life goes on.