Same. Especially since I've been building EDWs for most of my career. People are always surprised that it actually takes time to integrate with different systems.
"What do you mean you can't just pull all the data out of this system that we don't have database access to and are still building out the APIs?"
I kid... The people asking for stuff don't know what backend databases and APIs are.
I prefer a hybrid approach. A document explaining some common things to do and generally the idea behind why the API is structured that way (shows me you actually thought about it, and makes it more logical to find different parts of it without necessarily looking it up), and then an API spec showing all the parameters.