^* Hanging around upside down is inconsiderate to your crewmates for another reason. It’s hard to understand what someone is saying when his mouth is upside down. We rely on lip-reading more than we think in everyday conversation. Astronaut Lee Morin told me that it’s very hard to read someone’s lips if he or she is tilted more than 45 degrees. Plus, he added, “you get the chin thing.” Chins look like noses. Very distracting.