1. Going barefoot on board: If you don't have socks then you have to keep your shoes on.
2. Putting used gum on the safety instructions card: Just find a receipt or ask around. While you may not care about your livelihood in case of an incident, others may.
3. Overly fragrant food: If you want to eat fish, go to a seafood restaurant.
4. Aisle yoga: Everyone is uncomfortable, so please wait until you are in a proper studio to do sun salutations and downward dogs.
5. Watching a movie or show without headphones: this should go without explanation.