Same way there are rules guiding the universe, there are also rules guiding the airspace.
According to a flight attendant, there are things you should never do when you board a plane.
1. To avoid embarrassment, don’t take a seat in first class – unless you have a ticket.
2. Don’t drink coffee or tea while on board. You really don’t know if the items used are thoroughly cleaned.
3. Avoid having sex on board. All eyes are on you.