Yosemite full and deep training

I wanted to look around for the best of the best training for OSX Yosemite.

Im tired to use only 1% of the operating system and I wanted a deep know-how of every little tiny aspect of it (like holding option key when an alert prompt copying file, selecting like 'keep both' change to 'skip', where da f**k is this coming from I have no idea!).

So I wanted to know from you guys, the 'real deal', the final training, where I can find it.

Cheers

David