In short, the optimist to the core, pushes away pessimism with
  the sheer force of their optimism. When something sounds good,
  they believe it and go with it completely. They're quicker to
  trust, even though they don't always think so or see it. They
  complain a lot because, at the core, they believe the world
  shouldn't be as it is... and they really believe it can get
  better.

  But a pessimist to the core, pushes away pessimism by HEALING:
  patching up the pessimism with a coating of optimism, or digging
  DEEP to the cancer of pessimism and extracting it... putting
  ointment in the wounds, all the while saying, "You'll be fine!"
  until the patient believes it... all the while thinking, "I hope
  the patient doesn't die".

  A pessimist _hopes_ it gets better, but doesn't expect it.