Air Vent: Your Headphones, Our Headache...

Serving a meal in the confines of an aircraft often feels like you are being "punked".  The task itself sounds easy enough, wheel the cart out and hand everyone a plastic tray and/or a drink.  Now...add some turbulence, the smell of stinky feet, a cart with wheels that are going in several directions, huge knees protruding out next to you, babies heads leaning into the aisle, shoulders that belong in NFL uniforms, a stray fart that no one seems to notice but you, and a plane full of increasingly distracted people wearing headphones.  Would you go through the drive-through at Mc Donald's wearing headphones?  If you did, would you take them off to order, or to talk to the person at the window while paying for your food?  Would you watch your waiter/waitress in a restaurant ask you what you wanted to order before taking off headphones?  Thought so.  So why, why, WHY, do people wearing headphones on the plane (virtually everyone that travels these days) leave them on when approached by a flight attendant, and wait until they have been asked at least twice what they'd like to drink, before removing them only to make you ask them again what they'd like?  Of course this is all precluding the ever present question of "what do you have?".  What I have...is no time to answer that question 150 times on your flight alone.  If you can't remember what you normally drink for breakfast, lunch, and or dinner, you might need to reconsider traveling alone to the living room, much less across the country.