Positive thinking is not a panacea and an upbeat attitude will not solve all problems. But in troubled times, I assure you that gloom-and-doom thinking virtually guarantees failure, and negativity is the death knell of extra-mile effort. So when in doubt, choose to walk on the sunny side of the street, for the bright side is the right side to be on.
Optimists succeed more often that pessimists if only because they try more often and try longer. Plus, many problems have a large people component to them and when you can energize people—get them focused and motivated, cheering and believing—unleash their creativity and initiative, you are usually a long way toward solving your problem.
Look for the best in everyone and every situation and you will find it more often than not. Call out to the good in people and they will respond in kind.
PS: This advice most assuredly includes your internal conversations.
“We have nothing to fear but fear itself.” — Winston Churchill; 1874–1965, British Prime Minister during World War II
“Where there is a will, there is a way.” — Proverb
“Fear is the mind killer.” — Frank Herbert; 1920–1986, “Dune”