“Why even take species-groups instead of groups defined by skin color, weight or height? Why single out one property and not others? “
I am not sure if this is accurate answer but I feel like bringing this up: in some cases we should single out some properties over the others based on their function in regards to our interests. Obvious example: separating men and women in combat sports.
Another important detail is that in ideal world we could evaluate everything on case by case basis instead of generalize. So in general it wouldn’t be fair let men and women compete against each other and we should separate them but if we would evaluate every single potential fight, we might find some cases where it would be appropriate and fair to let some man fight against certain well trained women.
Not a great examples and not really criticism, but I think it is but of extensions of ideas that you presented here (which I mostly agree with). It was just something that came to my mind as I was reading this (perhaps because of my martial arts obssesion?) and wasn’t really addressed.
Eat more slowly and take smaller bites of your food.
Small bite of delicious food is equally as pleasurable as a big bite. Eating delicious food for longer and savouring its taste increases your pleasure from it. As a bonus, if you are trying to lose weight or eat less of something, you will end up eating less (you get full sooner) and digest better, too. It is trivial thing, but adds up to quite a bit of extra happiness over a lifetime.
I often use "What are you up to?" as it seems more natural and can be used almost in any context.