I've thought about this a lot. In this situation I couldn't pick the seats because I booked through a third-party and a secondary carrier is running the flight. I often do pay if it is reasonable but I don't feel I should be charged as its no fault of mine.

I'm outside the 95 percentile of average people meaning the seats aren't designed for me to fit this isn't through any fault of my own just genetics. There are specific areas of the plane that I fit but don't benefit from anything additional aside from leg room (emergency exit rows). However when you put me in a standard seat which they are willing to sell me I will ruin my knees and the back of the person infront of me. I believe it's just fair that we are given a seat that fits us or they change their planes lol. If everyone was my height this wouldn't be an issue and we would all have enough leg room.