If people would just
People use the word just a lot when talking about problems. If people would just drive slowly near schools. If people would just pay their taxes. If people would just follow the rules.
It's a sentence that sounds reasonable as it's true that most problems would go away if people just behaved. The thing is, they don't...and they probably never will.
This isn't a cynical take on humanity (I think most people are decent). It's about designing good systems. The vast majority of people who use Bear are there to write, and most drivers in my city stop at red lights. But "most" isn't "all", and when you're dealing with thousands (or millions) of people, a small percentage is still a lot of people.
Let's say 1% of people are going to misbehave. That doesn't sounds like much, but if 10,000 people sign up for a service, that's 100 people trying to break things. You can't plan for the 99% and hope the 1% sorts itself out. The 1% is where all the work is.
It's also not always the same 1%. Decent people have bad days. Someone who usually stops at a red light might run it accidentally when they're distracted and late for work. Some people genuinely don't know how to recycle properly (a pet peeve of mine as all my recycling feels pointless once I put it in the apartment block's recycling bins which contain un-recyclable trash).
Expecting people to just isn't a solution, it's a wish. The useful question is "what happens if they don't just?"
I wrote about roundabouts a while back and mentioned implicit and explicit rules. A no-parking sign is an implicit rule. It relies on people choosing to obey it, with a vague threat of a potential fine. A tree planted on a sidewalk is an explicit rule. You can't park there, mate. A traffic light asks you to stop. A roundabout makes it physically difficult to not slow down.
Bad systems punish everyone for what a few might do: bank KYC and airport security are two I've had to deal with in the past week that annoyed me. They treat every person like a suspect, and punish them accordingly.
Good systems work like a tree on a sidewalk. They don't rely on goodwill, and the people who were going to behave anyway barely even notice them.