If you're a woman and you kind of squat over the toilet seat you can take a piss standing up but 99% of the time you're gonna want to park your ass on the seat to go
I gotta sit or squat since I'm female. It's possible for women to stand to pee, but your body gets so used to sitting or squatting to urinate that it thinks you're not "ready" yet and holds it in when you attempt to stand.
Then there's the whole not being able to aim conundrum. Better to sit your lady ass down.
Once saw a girl piss into a urinal. Just sauntered up, put a leg on the wall to aim, and just went. Then just turned around and walked out. Sexiest shit I've ever seen.