Conversely, Japan seems to get by fairly well without said slack whatsoever and a largely conformist society as a whole. Case in point, restaurant menus. Changing anything about your order is practically non-existent outside of maybe some Western chains. If it's not on the menu, you simply can't order it. All burgers come with tomatoes? Too bad. McDonald's Japan will not even sell you a large water. Even if you offer to pay full soda price, or even if you tell them to pour the soda out and then fill it with water (which is otherwise free), they simply refuse.
The same situation with the bus driver would also never happen, they could easily get fired for allowing it. Train conductors even have to apologize for being early. There's also a lot more open racism and discrimination in various ways (example: drinking bar admittance or apartment rentals) and in various parts of their society that goes completely unpunished.
There is a LOT of slack in Japanese society. Using umbrellas while riding bicycles. Not wearing a helmet. Just two examples off the top of my head.
Lots of slack granted to foreigners who aren’t expected to know the rules. Lots of slack granted to Japanese people who are free to be normal, hikikomori, nerdy, NEET, sporty, etc. Slack to be and do whatever unless you bother someone.
It’s just slack you don’t really notice immediately unlike the menu stuff.
I wouldn't call those slack in the same sense of the word because rules aren't being bent or ignored. Helmets and umbrellas are things that are simply too widespread to have adequate enforcement on, same for seatbelts in most countries... so I don't consider that actively letting it happen or "slacking" the same way.
Foreigners might have some slack in some ways but in many ways it's quite the opposite... so there's both good and bad IMO.
"Free to be normal etc." I don't consider that slack either, that's just having a generic free society to me.
The same situation with the bus driver would also never happen, they could easily get fired for allowing it. Train conductors even have to apologize for being early. There's also a lot more open racism and discrimination in various ways (example: drinking bar admittance or apartment rentals) and in various parts of their society that goes completely unpunished.