Optimism," said Cacambo, "What is that?" "Alas!" replied Candide, "It is the obstinacy of maintaining that everything is best when it is worst.

What a pessimist you are!" exclaimed Candide.
"That is because I know what life is," said Martin.

One day everything will be well, that is our hope. Everything's fine today, that is our illusion

Optimism is the madness of insisting that all is well when we are miserable.

What passes for optimism is most often the effect of an intellectual error.

Are you an optimist or a pessimist?"
"I can't remember. Which?"
"Do you know what those words mean?"
"Not really."
"An optimist is positive and hopeful. A pessimist is negative and cynical."
"I'm an optimist."
"Well, that's good, because there’s no irrefutable evidence. There’s nothing that could convince someone who doesn’t want to be convinced. But there is an abundance of clues that would give the wanting believer something to hold on to.