Ask HN: Just bought my first Mac. What should I know?

Today is the first time I get to touch a MacOSX machine, on top of that I get to do it on a wonderful newly purchased Macbook Air. This after using Linux for the past 10 years. The world is shining with glowish colors of joy today.

What should I know, both practical and ethical/cultural about my newly chosen eco/techo system?