If airplanes were made for comfort, they wouldn't have so many seats crammed into the aisles. As it is, sitting next to a stranger who might not respect your personal space is bound to make you wish you'd never left solid ground to begin with.
A Reddit user by the name of Tessy23 took to the popular Am I The Asshole sub to ask if she was in the wrong for buying an extra plane seat, and then not letting a man sit in it to be next to his girlfriend.