Ask HN: What Git features would you like to know more about?

Hey HN!

What parts of Git do you wish you knew more about? Anything from things you've looked at but not grokked to cool things you've heard about and you'd like to know more about.

I've done Git training (on-site and web-based live classes) and I'd like to create some tutorials and such that are more asynchronous.

So, what would you like to learn more about?