I just faced this - I was trying to write a somewhat complex MongoDB query and I decided it was finally time to read a book rather than just cutting-and-pasting from stack overflow until I stumbled across something that seemed to work.

So of course in our status meeting yesterday I had to say I hadn't accomplished anything. In the long-term it's good to have someone on the team who really understand MongoDB. In the short-term it looks like slacking off.

- Of course my conclusion after reading about MongoDB queries was to decide that I wanted as little as possible to do with MongoDB queries and am going to avoid them at all costs.