For us supper is a family meal. We make something from scratch - then we sit down and eat.
I eat what he makes, and he eats what I make - that's common courtesy. I cannot believe that so many people think it's OK to make new food.
I cannot imagine not eating what was made for supper. That's just plain ridiculous.
We respect the other person when we cook - so I don't use mushrooms and he doesn't use ground beef. If DD has a like/dislike we'll respect that.
Maybe money's a factor. We don't have the money to make more than one thing - even if we used the leftovers. Well - I guess we could use them for supper the next night, but neither of us like to eat the same thing 2 suppers in a row. But our lunches tend to cost alot less than suppers. So - there's no way we could afford to make 2 suppers and then take leftovers for lunch. That would double our supper budget - and drastically increase our food budget.
We eat from scratch also, but it's something simple like stir-fry or eggplant with tomatoes and mozzerella under the broiler.
Also, I don't make "new" food or 2 suppers. I tell ds he can help himself to a container of yogurt or a bowl of cereal.