Kinda off topic, but worth to question. I always wondering what if we train a child to react the other way round. A happy moment, we hit him, force him to cry. When sad moment, we trained him to laugh and smile.

This might be able to prove that emotion is just a state of mind which let the people around us know we're happy or sad.

By DEFAULT, a baby will cry and laugh to show it's feeling. What if we change the default by training? I am sure this can be done. Agents like CIA, FBI or actors can control their emotion perfectly. Some of the soldiers even have no emotion, or blank. Not to mention actors and actress that won awards for outstanding performance.

How does this justify what is happy and what is sad, tangible and intangible?

Can we 'cheat' ourself that the moment is happy where in fact it is a sad moment? Is it possible that our brain fail to interpret the moment ? Some situation like a man expecting a baby so much, when the wife finally delivered the baby, the wife passed away. Will the brain try to logic that moment - 'Wife died, don't be sad, there is still a baby = Happy' or 'Wife has more memories, baby is new = Sad'. Or our brain has a weighing system, by adding the points to summarize the emotion -'Wife passed away + new baby = -10 + 5 = -5(Sad).

What about the time factor ? When we break up, we feel sad. after 2 months, we feel less sad, after 2 years we don't feel sad. Does time reduce the feeling, or the clock in our brain is telling us that '2 months passed, minus 50% of the sad feeling from the breakup'

Of course, if we put this in a general religion perspective, God created us so that we can live in this world. We should define our own path and livings, to achieve happiness. But how to define this happiness, does happiness measured on the last second in our life? Such as the moment we died, if the moment of the last beat of our heart is happy, we achieve happiness.