How much better can you be in your life, or could you have been, than what you are?

Many people have regrets, thought about their past, and felt that their future became bleak, if only they had done certain things, or been better at something, or tried harder. Or in the present context, they should improve themselves to achieve more, or change themselves., but just have not been able to do so. What can you suggest to improve or lead us to be better human beings or motivate somebody to reach that next level? I have my own views, but I am interested in yours. If you have a specific example of what you are aiming for, how you intend to achieve it, I believe it might help those with their own challenges. Thanks for considering my question.