if your ass is about to explode, your main concern is going to be getting it over a toilet

There's a lot to be embarrassed about, actually. Pants round your ankles with nothing to cover yourself up with, unless you're an exhibitionist nobody likes feeling exposed, especially unexpectedly. Even if the act of going to the toilet doesn't embarrass them, having your ass and genitals very likely on show to a bunch of strangers likely would. Not to mention the sounds and smells which some people find embarrassing even in their own home with the doors shut, especially when both are significantly more violent due to an upset stomach. I notice you're a male, for females this is often a very touchy and embarrassing subject, given certain social stigmas and expectations. Surely you've heard the "women don't shit" comment men come out with like it's some hilarious joke memore than once. It is treated much more of a shameful thing for a woman to do or be open about than a man. Clearly you've never been in a women's public toilet, i think a lot of men would be surprised if they heard the nasty comments some women come out with. I've experienced many times someone walk in and shout as loud as they can "EW, some dirty bitch has had a shit in here!" Or laugh and comment how disgusting and embarrassing it is when a woman in another cubicle accidentally farts while urinating, which is uncontrollable for women given the seated position to urinate. They hang around in their groups waiting outside the cubicles to see who the woman is who farted/shit, then give them dirty looks and make further nasty comments to/about them between themselves. You'd think they'd committed some god awful crime the way they get judged by some, hence how it can lead to it being really embarrassing when you simply cannot avoid going in public, for fear of how malicious and bitchy women can be, and how some men will act like it's disgusting and off putting and unattractive to experience a woman do that, even though they obviously know they do.

I feel like you've had some bad experiences in public washrooms.

Unfortunately, yes, i have. I have really bad social anxiety, plus OCD about using bathrooms, which has on multiple occasions gone badly for me. It takes me longer than your average woman to go for a wee because i have to do it in a ritualised way to placate the OCD. Many times during school, with maybe 3 working cubicles between the potential 500 plus females who could need to use them in the 5 minutes they were open at break time, i often came out to a long queue of tutting, accusation throwing girls. Given i was the resident nerd, i already got bullied at the best of times by a lot of these girls, and their dirty looks, staring, "What were you DOING in there" and "Took you long enough, did you have a shit?" comments followed by their nasty giggling, caused me a lot of embarrassment, nearly every day, for years. Not that you actually wanted to know that.

Wow, I'm really sorry, Ms.Katieface, I can somewhat relate to your experience, kids can be cruel. Hope you don't let it get you down. I admire your bravery for talking about this.

Huh, cool! I've never been to England, so I didn't know about that, I know when I lived in the States it was typically in the back, (for a bus at least, trains weren't really a thing in the part of the country I lived) and the trains here in Canada where I am now don't have washrooms at all as far as I know, nor do the buses. I guess it must vary.