About happyness and positive thinking

In my previous post "Positive thinking" or "joy of the life" I began to think about this idea (excuse me if I'm too noisy):

Too many persons in this world are unhappy in this or that way. That is why there are so much negativity all over the world.

I suppose every person has to be naturally happy, optimistic. Joy of life has to be instinct of survival. That is why, I tought, to find the medicine to have a happy world, we have to touch this cord of our essence.

Technique:
Buddhismus, as science of the mind with 3000 years of experience, says: we have negative mind.
In the post Raja Yoga Meditation for positive thinking I write about the technique of creating this positive direction of the mind. More related posts with this type of technique:
Emotional mistreatment -"bad" chief, parents, friends
How to do?-Everyday meditation for everybody and disrespect and emotional mistreatment

But this is about a very hard work.

Now I wanted to discover what is related to instinct. This is what I found:

1/ naturally happy are children. Why?
No responsability, safe and protected, no thoughts "accept-not accept" others myself -I'm loved by my relatives so as I am, no fight for the place under the sun.
( I don't see the life through the rose glasses. I speak about HAPPY children of all species -this is behaviour of birds, mammals, and humans too).

2/ happyness brings us our duty, says "Bhagavat Ghita". (You are educated to be a worrier to protect your earth and people. Discharge your obligations.)

3/ you make happy your body, when you move.