Thinking about how you can solve problems. A problem is just an unanswered question. Put your brain to use and think about how you can solve problems. There are a lot of those on this earth.
Stop Spending So Much Time In Your Head
Darius Foroux

This is a powerful personal philosophy to improve productivity and happiness.

Darius Foroux, it reminds me of these words I live by.

“If a problem is fixable, if a situation is such that you can do something about it, then there is no need to worry. If it’s not fixable, then there is no help in worrying. There is no benefit in worrying whatsoever.” ― Dalai Lama XIV