Milk. It's in our coffee, on our cereal. We see it in processed form - yoghurt, butter, cheese, skimmed and lactose free. It's there in almond form, or made from oats or soy, and is as lauded as the 'perfect' food or lambasted as not fit for human consumption and a toxic planet killer, depending on who you trust. Which type you drink, whether you were raised on breastmilk, what you think of it, is affected by culture, biology and fashion. How you...