One of the biggest challenges in being alive is that we don't have an A/B test available.

We are all born with certain tendencies, predilections, weaknesses, etc....but we are born blind to them. Because we can't "swap out" to a different person, we must stumble along in a blind walk and slowly learn these things by trial and error.

This is a very slow process and sometimes it takes you a decade to realize "why haven't I started doing XYZ before? or more accurately....why didn't I stop doing XYZ long ago??"

As such, I tend to feel that the "best version" of myself is most recent version. Yea, I'm not as young or fit (or have the same amount of hair) as my younger self, but 'this version' always feels the most content.