those laws you know and remember don't matter when you go one state over
That's not entirely true for a large number of reasons, not least of which being federal law. We also have county and local levels of law. You're also implying most of us actually bother to learn every law, which is actually not true, we mostly learn the ones that apply pretty much everywhere...
For the most part large parts of the law are usually similar enough or outright the same in nearby areas on any level of the law. For example, things like littering, jaywalking and murder are pretty much always illegal on the local level. Granted none of those three are ever properly enforced, which in the former and later cases, is always a bad thing (and the former can even lead to third degree murder of innocent animals, which is illegal under federal law and most likely California state law).
We have FBI, highway patrol/state police, sheriffs (county level) and local cops (the ones at the center of recent controversy, though the FBI can be just as bad at times, not sure about the other two though).
More or less yes.
I mean some things are just braindead illegal like murdering someone, robbing them so yeah that's just a nobrainer.
But when it comes to laws about sexual stuff from when someone is legal, illegal, when they can dress how they want, date who they want etc, it becomes really really muddled across the world and even in the US.
No seriously, look up the age of consent in the USA, it's different in nearly all states with different mandates for different ages.
On another hand we also have trouble when it comes to creating ''art''.
I am using ''art'' loosely because to some people, dressing up a virtual character in X way is NOT art, and to another it is.
For instance creating a character that looks like a F1 racecar is pretty badass and art in my opinion while just blankly putting a single skimpy swimsuit on a tiny loli is not, but in the general sense, that too is art.
And when does this art start to hurt somebody? That line is ever so blurred and thin over many countries and laws.