I recently paid bottom dollar for a flight and was annoyed when my knees jammed up against the seat in front of me. I had to contort myself a bit to fit.
Then I chuckled at the annoyance since I, myself, had decided to get the dirt-cheapest flight available. Couldn't even be bothered to pay +$15 for an emergency exit seat.
...And I would've done it all the same again for that 2 hour flight.
I just saw a Reddit thread where someone asked how many people would pay extra for a flight with no babies allowed. I had to roll my eyes at every commenter who said they would.