Most travellers who come to airports are totally stressed out due to sleep deprivation. They figure they'll come to the airport and sleep on the plane. While they're getting to the plane, during ticketing and at the waiting area, they become enraged and cause problems for everyone else. My suggestion is to advertise to all travellers on their tickets and electronic tickets, to get enough sleep before they travel. For those who can't, airports should provide Zen meditation areas in the waiting areas before boarding the plane, where the sleep deprived could plug in to soothe their nerves. Serve some green tea as well. Ensure that travellers don't drink alcohol on-board. This is all absolutely necessary in order to avoid chaos on the aircraft.