Horror is flying an airplane filled with too many narrow seats and being seated between individuals who would be given 2 seats if seats were distributed via percentage of total passenger mass.

LOL!!! I once had to take a flight on one of those little puddle jumpers with 1 seat per row on one side and 2 seats per row on the other. I was unfortunate enough to get a seat in the row with two seats. I was sitting down when I saw this big fat slob who must have weighed 350 pounds walking toward me :( You guessed it - he had the seat next to mine. The next thing that the fat slob (a stranger that I had never met before) did was to raise the seat arm that separates the 2 seats. I asked him exactly what the hell he thought he was doing. He said that he needed more room and wanted to get comfortable. I promptly slammed the arm separating us back down and told him "I paid for this seat and I do intend to use all of it for myself!" Can you even imagine the nerve?