As a woman I find it infuriating that I sometimes spend a fuck load of money to look more attractive just to be beaten by the hot girl at mcdonalds in a 2 dollar t shirt.
I guess you could say women HATE other attractive women, we hate them so much lol.
I find it kinda wholesome how men on the other hand just support (or are just indifferent) each other in their persuit of looking better.

You'll eventually reach that point where you can acknowledge a woman is better looking than you, and that will not bother you anymore.
As a chick, I think we are all signed up into the idea that nothing about you as a woman is important other than your beauty.
You will lose every time you try to compete with other women.
It sounds incredibly simple, but once you are CONFIDENT, not just with your looks, but who you are as a person and what you represent, you will finally be at peace with yourself and won't compare yourself to others anymore.
I personally can acknowledge if a woman is more attractive than me. (No, this doesn't mean I'm better "than you)
I don't care because, I don't put myself in the competition that pretty much all women do leading them to fucking hate eachother.
That's retarded.
You need to get comfortable with the idea that you cannot look like a pornstar or model. I mean you can if you had the tools and money, I feel like that's important to mention. You can get surgery, fix things on your body you don't like or your face, get rid of your acne higher personal trainer to help you work out a dietitian. I mean what else could I list here?
That's not something everyone can afford or have unlimited access to.
Idk what I'm saying anymore. Stop comparing yourself to others.
As much as I'd love to agree with you, most of my girlfriend's tend to be quite competitive about looking the preetiest as well. And I too sometimes feel a bit pissed when something like what OP describes, happens. It almost feels like an emotion I cant control (like anger???)
For the longest time Ive been exposed to situations where my friends straight up hype up another girl bout how preety she looks only for them actually break their fake composure and bitch about how over dressed she looks the second she's gone.
And this has preety much been my experience with my girl friends in general since middle school. I suppose the mentality has been engrained in our minds by society. Or perhaps, it's some kind of an evolutionary thing.
I'm probably overthinking this.
I think you're right. Its a bit of both.
Evolutionary wise, more attractive mates tend to be first picking. We see this in birds after all, humans are just the reverse with the females instead of the males being vibrant.
However as a culture we have all been desensitized to the thought that women (and men) must follow a specific look standard, and if we aren't that standard we are wrong and not desirable.
This is made worse because there are people out there who know this equation and make money off of the fact they know there's a woman looking at some Victoria secret model going "I wish i could look like that" and will sell her a product for $$$ to "make her pretty" knowing it won't and she'll keep buying because society has brought that ideal.