If you have irritable bowel syndrome, it's basically hard to treat, very common, and solved by a simple thing: availability of public restrooms.

It's not a shame to feel the sudden urge to take a shit. What's a shame is blaming people for feeling the urge.

> There is no world in which a healthy person must shit on the street.

Healthy people are not the only ones a city must be designed for. From Wikipedia: "About 10–15% of people in the developed world are believed to be affected by IBS."

And note IBS is not the only reason to feel the sudden urge to take a dump.