Optimism makes you less likely to walk away while not actually increasing your chances of success. That means that being overly optimistic will make you stick to things longer that aren’t worthwhile. Better to be well calibrated. Life’s too short to spend your time on opportunities that are no longer worthwhile.
i think maybe a useful tool for working is; whenever i start believing things are impossible, i am simply tired and need rest. i can begin again when i have the energy to believe in possibilities. i am not a negative person, i am just exhausted.