Personal productivity, happiness and optimization algorithms

I spend lots of time wondering about the best ways to be both more productive and happy. Curiously, I'm coming to the conclusion that this is exactly what I should not do.

Being productive, like being happy, requires living the present moment, not thinking about it.

If you want to complete a task, the best strategy is just doing it! You might start by setting up a plan, a sequence of smaller actions that lead you to your goal, but once you have this, just do it. Spending too much energy re-planning and judging yourself along the way is just counter-productive.

Curiously, this is not easy! Our brain seems to have some bad habits hard-wired. Want it or not, we start thinking about the past or making predictions about the future. Worse, we start multi-tasking (as you read this blog, you might also be listening to music, doing some work, or chatting with your friends in facebook)
Perhaps the only solution is to re-train our neuron connections. One way to do it would be meditating or repeatedly performing a task that requires one to be focused on the present. Feeling, not thinking. After enough practicing, the brain should start rewiring.

I recently came across this famous Hemingway sentence:

“Happiness in intelligent people is the rarest thing I know.”

Perhaps intelligent people have the tendency to plan too much? Planning involves predicting the reward associated with a set of possible actions and choosing the best ones. What if the reward function is not easily predictable? Perhaps the best optimization algorithm in this case is a greedy one. Don't plan to be happy only next year or next month or even tomorrow. You are dealing with a real-time multi-agent system, you have only partial and noisy data about the world, the system is recursive, and finding the optimal reward is probably NP-hard-as-it-can-be!