I'm thinking about APIs that are like incantations - only one way to say them...

I'm thinking about APIs that are like incantations - only one way to say them right and if you deviate from their single-tick-pony usage found in the documentation or SO, then nothing works, nothing makes sense, no clues why it doesn't work

powerful API is usually not what people call a powerful API in tutorials.
a really powerful API is concepts are simple enough to understand that you can compose parts of API and things work & make sense

Regex and functional programming patterns come to mind