From the article, There has been a trouble that we (a flight attendant) can't control occurred in flight.
For example,the top three annoying behaviors involve the invasion of personal space: sitting in a seat that’s being kicked, smelling a fellow passenger’s body odor, and sitting behind someone who reclines the seat too far. So there’s no way to escape these annoyances when you’re 30,000 feet in the air. Overall there're an annoying behaviors to make a passengers will be getting an unsatisfied experience.