I should clarify: when I talk about documentation here I'm not talking about code comment style docs - I'm talking about "this is how to use this library / API" docs

If your code is clearly written and nothing else ever needs to call it then I don't particularly mind if there's no additional documentation - but if I'm expected to use call your library from my own code I'm very much not keen on being told I have to read all of that code myself just to use it!