DON'T: Glass-out. Glass was built for short bursts of information and interactions that allow you to quickly get back to doing the other things you love. If you find yourself staring off into the prism for long periods of time you're probably looking pretty weird to the people around you. So don't read War and Peace on Glass. Things like that are better done on bigger screens.
Rock Glass while doing high-impact sports. Glass is a piece of technology, so use common sense. Water skiing, bull riding or cage fighting with Glass are probably not good ideas.