A little bit of reclining means the difference between my head drooping forward or to either side if I fall asleep (very uncomfortable) or staying in a vertical position with the weight slightly on the back of the head (far more comfortable).

This is really a case of "don't hate the player, hate the game" (be mad at the airlines for packing people in like sardines, don't be mad at the people for trying to take a bit of extra comfort which has been made available to them)