The slices of cheese are analogous to each of our individual lives: it's boring, manufactured, and there is a wrap of plastic which define us as individuals but keeps separate from one another. The only good aspect of American cheese is that it is designed for melting, so in essence, by removing the plastic barrier that keeps us separated, we, like the humble slices of American cheese, can melt and become part of something greater than our individual selves (like a burger or a grilled cheese).
Or as Karl Marx once said: Life is plastic, it's fantastic.