The really big thing in Japan is you're not allowed to park ("litter") your car in the street. In fact you can't even buy a car unless you can prove you have somewhere on your own land where you can park it. It makes a big improvement to walkability and general attractiveness of neighbourhoods.

There’s a hack though, just put on your hazards and you can park wherever you like!

I’m kidding of course but I see many people do this and it’s super frustrating.

Also fyi, you can buy a kei car without a parking certificate