Well I feel like a proper piglet after reading this thread. We never have leftovers.
Chinese we order chow mien, rice, sweet and sour chicken in batter, some kind of vegetable dish (we're not animals) the children may have a small amount each, if it is just for us we don't bother with the rice. It's a lot but we eat it all.
Pizza, share a large, yep.
Indian, one main, shared rice, naan, yes eat it all with no problem.
We did start sharing a large cod and chips though as it was just too much potato.
We don't have it often though, so tend to just eat it and enjoy it when we do, I don't worry about the calories in a sitting as a one off every month or two, none of us have weight problems. I'm not much of a dessert eater though so will quite happily eat a lot of savoury stuff as I don't need room for sweet things.