Sometimes we get so caught up in just getting to our destination that we forget to be courteous to our fellow passengers & crew. Being courteous can spread  & makes air travel more pleasant. Because I travel so much I am uniquely suited for gripes from air crews & passenger etiquette. Here are a list of some starters:

1) Don't call a flight attendant a stewardess. Today, flight attendants view themselves as safety officers. They do much more then serve drinks. Many flight attendants are also male so stewardess is an out dated term.
2) Don't expect the crew to place your extra carry on in there crew luggage area. It's up to the lead flight attendant & it's a good ideal to never ask, but instead let them offer.
3) Don;t block the aisle. Allow other passengers to walk through by stepping into your aisle.
4) Place any smaller bags, brief case's under your seat. Passengers & crew consider it selfish to place a small bag in the overhead bin therefore creating less space for other passengers carry on bags. This results in someone having to check their bags.
5) Turn off your electronic devices while the flight attendants are doing their safety briefing. They are not baby sitters. There is nothing worst then a flight attendant having to tell you twice to turn off your phone. Follow the rules!
6) While in flight, go to the bathroom before your final descent. You don't know how long it will take from descent to the time you arrive at the gate. Crews hate when passengers get up to use the bathroom while taxing. Besides, it's against FAA regulations. This is also the same for departure. Use the bathroom before you board. I find the bathroom much more comfortable & roomier in the terminal then on the airplane.
7) After you arrive at the gate, don't overreach over follow passengers to reach your bags. Ask other passengers if they can reach it for you, or wait for some people to leave before you make your way backwards.
8) Don't leave garbage in the seat pocket. We are all adults here. The flight attendants come by 3 to 4 times to take up garbage. There is no excuse for garbage left behind. A messy airplane means it takes longer for passengers to board for the next flight.
9) Once you leave, don't come back on the airplane. If you forget something, tell the gate agent.
10)Don't invade others personal space. That means no kicking their chair, or leaning against someone. If everyone follow these basic commonsense tips it would make flying more pleasant for everyone.