Aleister Crowley told a friend he could make any random fall over without touching them. To illustrate, he walked behind a stranger for a block or so, matching his footsteps precisely to the stranger's. He then scuffed his heels, as if stumbling and falling. And the stranger fell over. The stranger had heard himself fall, and so he fell. If Facebook tells you that everything around you is sad and depressing often enough, you get sad and depressed. All hail the Great Beast 666 of black marketing.