Why Not White Bread?

Why Not White Bread?
    Jack took the creased letter out of his crisp starched jeans and stared at it blankly chewing on his already chapped lower lip.
  Go to Knobs Grocery Store and buy one loaf of pumpernickel bread.
Just one, you don’t have to stay there long.
Just buy the bread and no, Absolutely NO, running.
    The note was written by the insatiable Dr Marx.  Simple and concise, it was his assignment for the day. Well week really. Actually, it was something he had been supposed to do for the last two months. But Dr Marx had told him today was going to be the day. Today would finally be the day that Jack ventured out of his house and achieved this one seemingly easy goal. He had a feeling. Dr Marx was all about feelings in an empathetic, creepy sort of way.
  Jack grimaced and wondered if Marx had ever felt the spontaneous stickiness of cold sweat that ran down his back and pooled in his armpits, noxious condensation that reeked of spicy Mexican food or perhaps Indian, the revolting physical consequence from walking through those automatic doors. They could close on you at any second, totally dismembering you within the space of a neuron synapse. With technology today you never knew. The sensors could be faulty. Or even worse maybe the system could have developed artificial intelligence and decided they would start killing humanoids off for jollies. And portly Jack would be their first victim. The more their fat, the more they splat.
  And all those people touching everything with their grimy infected hands…you never knew what a person could be carrying nowadays. The common cold, the Bubonic Plague, who knows, Jack sure as hell didn’t. 
  Or maybe they were all aliens, an extraterrestrial infestation of the typical grocery store. They might realize that his brain would look awfully tasty with a side of tartar sauce. Their spindly fingers caressing ray guys hidden underneath cotton pockets. It could happen.
  Jack did not like Dr Marx. He wore loafers and not just any loafers, but ones that could have been purchased at a friendly corner store right after the Big Bang, moldy loafers with broken down heels that showed off Marx’s standard argyle socks. The kind of socks that women with craft fetishes liked to make into sock monkeys and everyone knows there is something supremely unsettling about sock monkeys. You never knew what they were thinking.
  And did the letters always say buy pumpernickel bread? Why not white or wheat? Jack absolutely despised pumpernickel. He had never tried it of course, but just the name made him nauseous.
  Jack glanced again at the blue ink and attempted to gulp in air that wouldn’t reach his lungs. His eyes wandered to the red Chevy that would transport him to Knobs Market.
The red was so bright that it would probably distract the other drivers and cause a five car pile up. The force from the multiple collisions would send him flying through his windshield and into someone’s impeccably groomed yard back broken, body discarded.
  He took one long step back into his doorway and onto his Formica tile. Nope, no grocery store today.  Why couldn’t it be white bread? He would have been able to do it if it had been white bread.