Need help with text!

Hi guys... I wrote a little text in English... Well, it may suck, it may doesnt... I don't know... But the thing is, English isn't my first language... So, I hope that somebody is ready to help me by correcting my mistakes... Thank you very much!

"A pessimist's life

Some people say, that life is nothing else than a boomerang. What one throws out, one gets back.
I, however, think that far too often you give, give and give and don't get anything in return. You throw something out there, but you lose it forever.
And over the past few years this belief has evolved so much, that it has almost become a fact to me.

My friends often say I'm a pessimist. Well, I agree. I do think this is a pessimist's attitude. But I've also come to the conclusion, that having this attitude is the first and the biggest step towards happiness.

I mean, think about it! The so called optimist usually claims, that the glass is half full. So this is why he just drinks the drink without even thinking. But the thing is, he doesn't really have any options, does he? I mean - rhetorical question - what's the point of filling a glass that already is half full?

A pessimist, however, has the big advantage of actually knowing, that the glass is half empty.
And what can you do with that?
Well, you can watch at it and either ask yourself, why the guy who intended to fill it - most probably an optimist - didn't succeed, or you can just accept the fact, that you cannot fill a half empty glass!

Hence, the pessimist kind of just copies the optimist's behaviour and drinks what's in the damn glass.
The only difference, though, is his motivation. He doesn't do it out of joy or lust, but because he wants to prove his point.
I mean, let's face it: Optimism doesn't do this world any good, for it only destroys people's hopes. Nothing else.

And that is another thing a pessimist knows.

A pessimist just knows. He knows what he does. He knows why he does it. He knows who he is and who he must be.

So, his problem is a different one: I mean, as soon as he's figured out who he really is, he stops wondering what he can and what he can't do. He then must find a way to stand out in a world full of ignorant wannabes.
And this - my dear friend - is a very delicate quest."