The human nature

This is my first post after a very, very long absence. I don't even know why I started doing this thing again.
I want... so many things. I got most of them. Any sane person, a person who would actually think with their brains, would be more than happy right now, if they were in my position, leading the life I am leading now. Don't get me wrong! I AM happy! My life is blooming and developing so perfectly right in front of my eyes. Everything fits in the right place. I think I am just suffering from that "human nature syndrome", how I like to call it.
You know, sometimes I think that whoever programmed the human beings, especially their minds, was either a sadist or a complete asshole who had no idea about what he was doing at the time. Why am I saying these things? Well, think for a second. Hasn't it ever happened to you that, when you think you have everything you could possibly want from life, something just has to come into the picture and ruin that illusion? Haven't you ever noticed that we, humans, ALWAYS tend to crave the most for what we cannot have? Haven't you ever noticed how stupid and naive we are by nature, that we make decisions by following our hearts, aware of the fact that we might end up suffering, but we are still convinced that we decided correctly and that's the way we should always do it? Haven't you ever noticed that we are always in search for something, somewhere, someone and that we are never satisfied with what we have?
Why do we still try to convince ourselves that it's good when we know it's not, just because our heart tells us to? Why do we still enforce ourselves to hope when, in fact, it really is hopeless? Why can't we control our emotions with a little bit more help from that thing called Reason?
Then again, it might be only me, since there are at least 4-5 people in my circle of friends, who seem to have achieved the performance of reasoning their feelings, of being happy with just themselves and feel complete within themselves. Am I the only one having lost the last piece of the puzzle of her own self? I keep looking.. and I keep finding random puzzle pieces...

Apparently it's just not the one meant to take its righteous place in my puzzle...