Basically I have noticed a way to tell the difference between Pessimists and Optimists, first of all let me explain what they mean for those who don't know:
A Pessimist is a person who expects the worst in a situation, they are very negative.
An Optimist is a person disposed to take a favorable view of things, they are very positive.
How do we tell the difference between them?
A pessimist is easily seen, he will always make the negative shown and hide the positive, lets take an example:
Lets say a pessimist gets a glass of water, half full of water, a pessimist is KNOWN to say "This glass is half empty" whereas an Optimist will say "This glass is half full", I'm going to use some one from Argonath as an example, it's actually quite comprehensible and easy to understand, just look at what people do, think about when they talk whether they are being negative of positive, another example: Optimist: "Can I have some more?" Pessimist: "This is not enough"
This is not a stereotype, you don't have to believe me, but I thought it was interesting.
Are you a Pessimist or an Optimist