The scene: A full premium economy class cabin.
Describe your fellow traveller: Huge middle-aged man. Not obese, just a big old lad.
The review: He crams himself into his seat which, although larger than a normal economy seat, is still barely enough to contain his bulk. It's like trying to fit a sofa onto an armchair. As we take off, he immediately goes to sleep, his leg of lamb arm taking up the entire shared middle arm rest, the sleeping breaths from his nose so strong they almost part my arm hairs. He stays, slumbering for four or five hours, an immovable man mountain, taking up too much room. Although he's not actively annoying, he's hard to ignore...just...laying there, being large.
Verdict: Imposing insomniac.