> But I've never gone to someone's house and seen their bathroom in that condition.

I broadly agree with your premise, but the nitpicky HN part of my brain feels obligated to point out that a certain amount of selection bias might be at play here. Public bathrooms are by definition places the entire spectrum of the public visits, and is probably a broader and slightly more diverse pool than the people whose homes you personally visit (unless you're a social worker, which you probably aren't because then you would absolutely have seen swathes of homes that a lot of people here would probably deem uninhabitable)

That said, you're not wrong : we've all witnessed friends, acquaintances et al behave differently from one context to another. I live in Norway, and the prototypical example that comes to mind is that kids / young adults here are significantly more belligerent and antisocial abroad than at home where they are subject to the Scandinavian brand of tut-tut judgyness. Basically the spring break phenomenon so it's not unique by any means.

Close to your point: https://en.wikipedia.org/wiki/Broken_windows_theory

Not exactly, but close enough.

Why would people want to do that, even if nobody is watching, that's the question we need to be asking ourselves.

One thing I find attract of anonymity is that a person can make statement without risking it being permanently associated with him for the rest of his life. He can test ideas, push boundaries, perhaps discover something about himself or his previous assumptions. We are only sharing information after all

If most anonymous speech were like The Federalist Papers then I would agree. I think the mean-value of anonymous speech is either zero or negative. I'm aware this is a feeling and not something I can prove.