Spanner
As an ATPL instructor I can back up Crepello assure you that, at some stage, the holder of an ATPL has learnt what happens when he "pushes a button", or makes any other action for that matter. He or she learns the general case here, and any specifics during the type-rating training. Some of them may not remember or connect all they know, but that is the case for any training. However I know many people who take great pride in knowing exactly what goes on in their aircraft, and they are usually the best pilots.
Couldn't even hope to repair the thing, even with 4 years training, so much respect to you and all the engineers I know. That is not my aptitude - I fly, I teach and on an academic level I understand the systems well. The rest I leave to the people who are good with machines.