I tend to agree with people who have posted that others don't care about our previous actions as much as we fear they might. I know I see others do or say things I think they might be embarrassed or regretful about but that thought passes in a nanosecond and I move on with my own life and my own concerns and don't give it a second thought. If the person is close to me I accept them for who they are and I really don't give it another thought. So it's really more in our own minds the regret we should just let go of. Maybe it's a good motivator for changing our own future but that's about all a memory like that is good for.