I can only think of three interpretations for "Are you going to finish that?" They are "Wow, I've never seen somebody eat something so big -- do you think you'll manage?", "Wow, I've never seen somebody eat something so weird/gross/whatever -- do you think you'll manage?" and "Hurry up, already. I want your leftovers." Since I'm not in the habit of eating unusually large or unusually weird things, pretty much any time somebody asks me "Are you going to finish that?", it's the leftovers thing. It's not literally, outright asking for leftovers, but it's going to be interpreted as that. —
David Richerby 1 min ago