Gender roles: by and large, they're actually pretty dumb! You know what communicative medium loves a good dose of dumbness, though? Memes, duh! Thus, they thrive on producing silly little images of anything that involves shaping the perception of a certain gender. It has to be said that there is a certain freedom to tell yourself that you're just a girl, and it definitely makes for some humor that many find to be relatable. It's true, there are simply some experiences that will be intrinsic to the person you are and not to others based on what social categories you happen to fall into, and the internet is there to underline that with an exclamation mark at the end. Girly memes are simply a product of that, and they do their job with definite creativity. Being a woman doesn't get better than all of this abstract funniness that people come up with.