Instead of being able to quickly peruse docs to see if a method existed and what it took/returned, I would be directed to dig through source code to see if it exists and what it did. This is basic API doc work. This meant something that should have been fairly quick took significantly longer.

Then there were times when I did dig through to understand why something worked. When I pointed out that something should be done differently (an id-lookup done hierarchal instead of flat) I was told "Oh that's deprecated, you're not supposed to be using that anyways". And how exactly am I supposed to know that?

Ultimately it was a frustrating way to spend a lot of time.