It only half explains it, though-I think most people have traditional Sunday dinners from a young age, and if I had have had that, I think I may have carried on having something similar when I got older, perhaps omitting the meat and replacing with something else...
But I've never done that. I know a lot of vegetarians keep up the tradition by cooking all the 'trimmings' (they're what make it different, really to most other dinners) and working around the meat.
This thread's making me want to attempt this, now lol