Improvements

This one little question has been bugging me for a while now... What needs to be done to change something in yourself that is obviously not good? It seems that just realizing what it is does not make it go away. Even if you do something and you think, "oh, that's no good, why am I behaving like that?" you still are often not sure how to answer that question. So really, can you pinpoint exactly why you're doing the things that you feel have some underlying source in your core being? I mean, you can understand some of it but how accurate is that? Some people say you can only know yourself - it's close to impossible to really 'know' another human being. Others say that you cannot even know yourself and I tend to agree with that other stance. The hardest thing for me would be to write an extensive characteristic of myself. One that would list the main qualities, traits of character, typical tendencies, give some explanation and justification for why I turned out the way I did. I feel it would always be incomplete, always fragmentary. Would other people's perception of me help complete the picture? Maybe they could see something that I cannot? What if I completely disagreed with some of the opinions - who'd be right?
Wouldn't it be fun if we had a machine that would test us extensively and spit out a psychological profile plus possible ways to improve oneself? We could still disagree, that's ingrained in our human nature to question and contest just about everything around us (which can have very different outcomes). But maybe it would help accept some of the things that we tried hard not to see and through a conscious analysis finally come to understand and manage to change the most distractive traits of character, tendencies, fossilized habits of our mind and body?
I don't know. I just feel that I would need to change so much about me to make me a better human being for people around me and for myself. I feel that some things have just gone terribly wrong and I cannot undo anything. I don't want to drown in a sweet blissful ignorance of my own shortcomings and suffer myself for the rest of my life. I would like to start living with a better, improved me. One that will just give me some fucking peace and quiet. Some ease and simplicity, less worries, more joy, a nice, agreeable human being. Is that so much to ask?!