What is the weirdest thing society collectively agreed to accept

[CrimsonFury]

Human society runs on thousands of invisible agreements that nobody really questions because everyone grew up around them

Some of these things make perfect sense once explained, but others become stranger the longer you think about them

Standing silently in lifts facing the same direction, pretending not to notice strangers nearby, paying huge amounts for tiny bottles of water at airports, or celebrating arbitrary calendar dates with enormous emotional importance all become slightly surreal when examined too closely

What social behaviour or system feels weird once you stop taking it for granted