Optimism... how difficult is it??

I have often heard about the powers of positive thinking.. always say "yes" . never say No. the eternal optimist wins. though these sound really good are we really able to follow them. Can we be olblivious to the outcome of a certain event. " Do your best and leave the rest to fate/ destiny/ god" . " do your duty and dont worry about the outcome". as good as these sound, i find this really hard to implement. I am no eternal pessimist but optimism also has a ceiling beyond which i am unable to penetrate.

Does being a realist signify that one is a pessimist. Just like we have different probabilities for a certain event , a realist would weigh all possible outcomes and reserve a judgement on it. More or less that closely correlates to the pessimism view. Can one be a realist and also be an optimist at the same time. These are thoughts which continue to repeatedly haunt me.

will i get a pay raise? well, hmm.. most prolly not, would i be happy if i got , hell !! yeah !!

Can you execute this work within this time? hell, no....

will you become a VP by 35? highly improbable, but yeah can try...

When can you buy a house in chennai? defly not, in the near future...

not sure if answers like these fall into the realm of realism or pessimism..

The emotional realist that i am guess am more comfortable of accepting reality and moderating my expectations rather than aiming for star and reaching the moon.

any ideas of how to balance realism and optimism...