I think there's too much randomness in air travel to evaluate anything besides price. Pay more for more legroom? Is that before or after the person ahead of yo

I think there's too much randomness in air travel to evaluate anything besides price. Pay more for more legroom? Is that before or after the person ahead of you reclines their seat? Will there be room to stow your small bag, or will that be where you want your feet to go? Will the person behind you put their feet on the arm rest and force you to lean forward? Will the person next to you be too tall or wide for the seat?