Many many years ago I read an observation that men tend to keep unchanged into their later years the hairstyle that they happened to have in the period of the lives when their were the happiest.

I think that probably applies to things other than hairstyle, like storage media :-)

I have tried to analyze about myself in which aspects of life I'm doing the same thing. It's not true for hair/clothing styles or tech. But surely I'm not so unique that I'm immune to this effect? I wonder if this phenomenon can also manifest in more subtle ways, e.g. you keep the slang from the time when you were the happiest, or the ideology, or etc. Might be true about music, I seemed to have stopped evolving in my music taste unless when I put in deliberate effort (which I rarely do, because I don't think it's something worth optimizing form).