People unaware of the laws invent things that are almost monads but break in edge cases. E.g. Scala's collections with flatMap where you can mix and match colle

People unaware of the laws invent things that are almost monads but break in edge cases. E.g. Scala's collections with flatMap where you can mix and match collection types are almost, but not quite, monadic. Javas Optionals as discussed in parallel threads are similarly almost, but not quite, monadic. And this kind of almost correct implementation is more dangerous than a blatantly incorrect one.