Today I'm wrangling with null versus undefined in TypeScript and making a bunch of changes just to deal with that. I know there is a semantic difference between the two but in practice most people use them interchangeably. It's simply unnecessary to have two ways of representing nothingness when most languages simply have `null`, or even eschew it altogether by making nullability sound, via option types as in Rust, Haskell, or OCaml.
