I think the capitalization of a method making the difference between two very different outcomes might be my favorite example. It's that kind of stuff that makes me happy I have to go through api reviews at work - although seriously how does anyone sign off on these designs?
I only wish people had to do that. Shit like this are why professional and civil engineers roll their eyes at the mention of software "engineering". There are best practices and available tools but people employ them far less often than they probably should. In the space, take a look at Kadena's Pact smart contract language. It's not perfect by any means (lisp-religious syntax and its tight integration with Kadena internal constructions, for example) but it is at the least, working on formal verification support.
