look up any word, like the eiffel tower:
 
1.
telling yourself that the outcome of a situation will undoubtedly be pleasant; when knowing that the truth is that it will not, so that your artificial smile and laughter will not and cannot be undistinguished between true and false. ultimately living a "happy" and "carefree" lifestyle that many people envy, not knowing that you are as miserable as they are. you just dont show it in public as they do. your glass has water in it. whether it is half full or half empty doesnt matter, but there's water in it and it's constantly getting filled and consumed
Optimistic pessimism isn't bad.
by Jeremy Beck February 11, 2008
 
2.
Hope for the best; prepare for the worst.
Optimistic pessimism is a great way to live your life, because you can't lose.

People who argue that optimistic pessimism - or any kind of pessimism for that matter - is a self fulfilling argument are just naive irrational pseudo-philosophical hippies.
by I hate optimists April 24, 2010