Interesting that no has mentioned FEAR as a factor in refusing upgrades. Statistically speaking, pax seated in the rear of the aircraft are safer should the unthinkable and thankfully rare disaster occur. At least that is my commonly accepted wisdom. People who refuse upgrades may be doing it out of a highly developed sense of self preservation.
Nevertheless, I _fearlessly_ seek the upgrade every time.
Jim ( who just saw a matinee of "Bounce" which is a two hankie movie )