This is an account of what was described as a

‘nightmarish’ flight:

It was a 13-hour flight that I will never forget. The trouble began when the passenger in the next seat to me boarded. He had just had bad problems trying to check in his luggage at the self-service desk and was very grumpy. I discovered this because he told me all about it. Then he told the man on his other side – at length. Then he summoned a flight attendant and told him all about it. By this time, I was starting to suspect that the man was . . . err, a bit more than obsessed. After a while, I started to work on my laptop. Then I became aware of an unpleasant vibration to my left. My neighbour was jiggling his leg so hard it was rubbing up against mine. He was also taking all the space on the elbow rest between us, which made typing impossible.

‘Please would you mind moving your arm?’ I asked.

‘What’s your problem?’ he snarled, clamping his arm in place. There were 12 hours to go. I gave up typing, jammed on my headphones and prayed for sleep. He also, presumably started listening to music, because he began to jab his hands in the air and sing, loudly. I asked the flight attendant for another seat, but the flight was full.

What could be done to improve the service quality of this flight, as perceived by the narrator?