You will drive by an almost deserted gas station on a side street, sandwiched between Cambridge homes and vacant storefronts. The clock reads 11:15. "US Petroleum" letters shine in fluorescent red and blue, fuel at $2.99 a gallon. As you turn, you spy an old man in a moss green sweater and turban shuffling in the shadows, waiting for customers to come. Your mind will take a mental picture of this moment. It is the saddest thing in the world.