Eating aboard public transportation is akin to wolfing down a burrito in a bathroom stall. Technically you're not breaking any laws, but you're still disgusting. You have to be seriously uninhibited to just chow down on an egg salad sandwich in a crowded Red Line car. The smell is vile, people around you are judging, and that seat you just set your fork down on was ground zero for a prostitutes bare ass, like, three hours prior.
Look, we get that you're hungry. But that fish head curry can wait three stops until you get to your apartment. Have some respect for the people around you and, to that point, for yourself, by eating at a table.