am mostly happy with a few sad moments every day or two that don't last more than half an hour .. i got a few plans so probably i can be happier in the future

..
I think happiness for an INTP is :
1. when they believe that people r made rationally as for every thing that cause sadness , there is a thing that cause happiness in their life in return, and if they decided to crush the balance , they must be prepared to lose a few things ( that might be important to them ) in order for the happiness parameter to get back to its natural place ..
(
you know like when Einstein lost his wife and child in the way of proving his theory :'( .. i almost cried at that moment )
2. when they r content about what they have materialistically but r still eager to improve themselves as human being and be useful to the world , to do that they might need materialistic things and for that reason they can be unsatisfied .. not for the mere reason of wanting to own something ( money , authority , power or whatever ) ..
3. whenever they'r doing something they love passionately and it end up with a result that is much better than what they'v expected
4. when they try new things and/or break into a new unexpected thrilling experience and get out of it alive

.. or satisfied and happy for taking the chance and not feeling the usual afterwards regret .
there are many other reasons but those are the main ones i guess