I guess I should give a bit more details on my opinion: if the flight is short, no need to recline. Sorry, that is my opinion. My DH flies twice each month, so is no stranger to airlines and normally is upgraded to first class where it's not an issue. However, when we travel as a family and sit in coach, we notice it's usually the "newbie" travelers reclining, as if to say, "Oooh, reclining seats! Let's try it out!". Of course there are those who are sick or need to recline with a baby - that is life and is par for the course of air travel. But on a short flight, no baby, no illness, nothing like that...don't recline your seat. It just doesn't make sense and causes discomfort for the people behind you. Yeah, you paid for the seat, sure. But the person behind you paid for his/her seat too - including the "airspace" around it!
Frankly, I think airlines should be ashamed of themselves for creating these cramped spaces, reclining seats that have no business reclining, giving rude service by flight attendants, and charging an arm and a leg to be uncomfortable!