What is 'seat anxiety', which is making people pay ₹17,780-cr 'comfort tax' annually in UK?

Millions of adults in UK decide against attending weddings and taking flights because of "seat anxiety", a study revealed. It refers to the fear that they won't fit into seats on flights, sit on plastic chairs or would feel uncomfortable using bar stools. To avoid hassles, people are paying ₹17,780-crore "comfort tax" annually for upgrades and extra legroom.