The following is a real story.

(edited excerpt from “The power of habit: Why we do what we do in life/business” by Charles Duhigg)

LONDON UNDERGROUND
Philip Brickell, a forty-three-year-old employee of the London Underground, was inside the cavernous main hall of the King’s Cross subway station on a November evening in 1987 when a commuter stopped him as he was collecting tickets and said there was a burning tissue at the bottom of a nearby escalator.

More than a quarter million passengers passed through King’s Cross every day on six different train lines. During evening rush hour, the station’s ticketing hall was a sea of people hurrying beneath a ceiling repainted so many times that no one could recall its original hue.

The burning tissue, the passenger said, was at the bottom of one of the station’s longest escalators, servicing the Piccadilly line. Brickell immediately left his…