Hell, I do significant amounts of server/Linux work, and still don't understand Docker (it doesn't help that I haven't been able to run it because btrfs).

I understand that it's a lightweigth container, but what's the advantage? Aren't images still 2+ GB? Do I have to version the entire FS instead of 2-3 config files? Can I freeze it? Can I push it to a server? How long will that take? Can I use the same image on develop, staging and production? How does it know which is which?

Etc etc.