I agree. The Green Car is not like first class on some European trains, where you get special extra freebies. You just get a bigger seat.

I'm tall enough to loathe almost all coach airline seats, but the only time I've felt cramped on a Japanese train is on one of the few surviving local choo-choos with pairs of two-person hard bench seats facing each other. Those seats were obviously built in the days when everyone had short legs, and if the car is crowded, you play "you put your knees here, and I'll put my knees there" with your fellow passengers. However, these trains are gradually disappearing, and you are unlikely to find them on any but the most remote local short lines.