Yesterday I was racked with guilt. Yesterday, my son woke up from his nap before I had a chance to pick my daughter up from school. Since time was short, I trundled him into the car with me. Of course, the short trip turned into the stuff nightmares are made of. The kids bickered and kicked and cried. They fought over the cupcake my daughter had made in school and didn’t want to share. They took everything out of her school bag and threw it around in the taxi. By the time we reached our apartment building, I was a …