Sometimes doing the right thing makes a big difference.

in 1983, Petrov, a Soviet Lt Col, received multiple reports of US missiles being fired at the USSR but decided not to report the missiles to his direct superiors, who could order a retaliatory nuclear strike.

Petrov decided that the reports were more likely a system malfunction than a genuine attack from the US.

He was right; the detected "missiles" turned out to be reflected sunlight.