[prayag]

>Even comparing your present self to your past self is fraught with numerous biases.

This is definitely true. But you probably have a better idea of how successful/happy you were 2 years ago than your peers right now.

>Moreover, on which dimensions are you going to compare

Yes the dimensions have to be defined. If you wanted to be more creative or wanted to live abroad (assuming you are not from France), then you have progressed in life. But if you wanted to write more software than this is a regression.

>Key should be to not overanalyze life, but rather simply live it as if it is not that important.

Different strokes. You don't have to. But if you ever ask a question to yourself about whether you are successful or not, or happy or not you might want to measure somethings. I don't think it's a bad idea to look back once in a while and see where you have come to in life.