Many people say that the Doctor is too pessimistic, because he believes, “Always expect the worst, and you will never be disappointed.”  Really this means, if you always expect the worst then everything is a wonderful miracle.  He was recently (6-Oct-2008) vindicated in this piece by Nikki Tundel, The Upside of Pessimism where she talks with author Joshua Foa Dienstag about his book, Pessimism: Philosophy, Ethic, Spirit.