When groups of people get into an elevator they usually stop their conversations and become silent all of a sudden and the silence sometimes suffocates everyone there but no one says a word until they get out the elevators. I think this is good gesture which ensures that the elevators riders don't bother each other with details of their private lives. When the same group of people get into a public transportation system like a bus or a plane this rule somehow dies.
It is really difficult to listen to people elaborating the tiny details of their lives loud enough for at least 25 passengers in the bus or flight. I recently had a horrible experience in a flight to Austin when a lady behind me started playing with the small kid of another passenger. She was so loud in here conversations to the baby that made me believe that either baby has hearing difficult or she wants everyone else in the plane to know that she would become and excellent mother if given a chance because she is totally capable of singing all the nursery rhymes loud enough for 10 or 25 kids..
If people could extend the elevator silences to buses and flights or at least keep the conversations quite know for 4 or 5 people around them then public transportations would be much better experiences.