I'd like to think that anyone can change for the better if they are committed enough to the change. I suppose a person's environment, personality, etc. would have some bearing on how hard they would have to work to change. For example, being around profoundly negative people would make it much tougher to improve one's self. If someone significant in your life is constantly telling you that you'll never amount to anything, you'll have to work mighty hard to overcome it. That would be one huge chunk of metal to be carrying around in your backpack.