Make eye contact. Say "please" and "thank you". Remove your earphones when asked a question. Be nice to your fellow passengers. Want to alienate him or her instead? Borrow a pen and don't give it back. Complain that the passenger ahead of you has reclined his seat. Snatch newspapers off the top of her crew bag. Stand so closely behind her in the aisle as she serves beverages that when she bends over, her rear end rubs against you.