I used to have a goal of "personal completeness," or something like that at least. That was my driving motivation when I was younger (teens and early twenties). It's stuck with me ever since, though I no longer believe that "personal completeness" is even possible.
Improvement is possible, but let's parse.
On the one hand, there's learning new skills and abstract information, or improving one's physical fitness. Learning to play the guitar or shoot a rifle or sew a dress from scratch or grow potatoes. All good skills to know. There's also abstract knowledge, like the philosophical differences between the Hinayana and the Mahayana, or the chemical basis of photosynthesis, or Thomas Jefferson's musings on yeoman farmers, or theories about Peak Oil. Also good to know, in moderation. And being physically fit is never a bad thing, unless it prevents greater pleasures.
On the other hand, there's being a better person. I guess this mostly means being nice to people. Or generally being happier ("smiles are contagious" and all that rot). Or focusing your mental energy on some bit of wisdom someone happened to write down thousands of years ago. This is what religion and philosophy usually boils down to. And if being nice to people helps you get laid, all the better
