Optimism itself has its ups and downs. It's not something we should be doing all the time. For example, I don't believe that next week, I should be optimistic about visiting the Philippines. I know it will not happen. Being optimistic is renewable--in the real sense of the word.

(In reply to a link on "optimism being a strategy for a good future")
P.S. I switched from Telefonica/Movistar to Vodafone and lost connection for nearly a week. I now regret switching to Vodafone ADSL. What a caper!