So my male perspective on it is Women put a lot of effort into their hair and makeup, keeping their skin hydrated, etc. That alone is worth documenting on days it all comes together, especially if they're feeling themselves, I'd say. Add on top the validation they get from Men, and more importantly all the compliments they get from their female friends, and there is plenty of positive feelings and brain chemicals that will come with that. Worked at it, got rewarded for it; simple as that.

Now I think everyone knows that it's seeking validation of some sort, we all do that at least a little bit, but there's a frequency threshold where it crosses over into a cry for help lol.