Yes, of course that's possible. Probable even, come to think of it.
What use is it to be that attractive? Probably not much. Two of the four most beautiful women I've ever seen were at the cash register in a shop. (One of the others, the most beautiful one, was probably a university student (in Louvain, long ago); I've no idea about the fourth, but she was in my local shopping center, which isn't a glamorous place.)
If my family history is any indication, I'll probably die from cancer at some point. In that case, I'd love to sign up for such an experiment.
"Your reason and your passion are the rudder and the sails of your seafaring soul. If either your sails or your rudder be broken, you can but toss and drift, or else be held at a standstill in mid-seas. For reason, ruling alone, is a force confining and passion, unattended, is a flame that burns to its own destruction."
—The Prophet by Khalil Ghibran
I stopped drinking ~9 years ago. It's nice to think I'm not benefiting only myself, but society as well! BTW, if anyone else wants to quit, Allen Carr's Easy Way to Control Alcohol really did make it easy!
I was surprised reading the title, because usually people don't seem very happy to me at all. But I was thinking of when I see them in the shopping center or the train station...
In the Netherlands where I live, people mostly think AC at home is too expensive for that one week a year when we'd use it.
I think that moral realism is true, but species-specific. Morality is basically what being a social species feels like from the inside. To be able to live together, group members need to behave morally towards each other; if too many don't, their society falls apart. But our human morality is different from what it would be if we were more like e.g. lions or naked mole rats. If we create an AGI, it will be its own species. Will it be a social species, and will it see us as their in-group?
phenomena
typo: should be phenomenon
Some more low-hanging fruit for improving your appearance: just don't have any holes in your clothes at all; toss anything with stains you can't get out, and anything with frayed and/or overstretched edges anywhere, and any faded clothes – they always fade more in some places than others.
You mention posture, and yes, good posture is very attractive, and people will respect you more, too. Also this is definitely one area where improving does help you "become a better person", or at least feel more confident and "agentic"; at least, that's how it's worked for me.