It started as a mark of disrespect, and cascaded into a global phenomenon. The simple act of wearing sunglasses all the time took the world by storm.
It started on the Doctor Phil show, when one of the participants decided that Doctor Phil's advice wasn't worth a shit. Instead of arguing or turning away, the person merely put on their sunglasses and responded to everything Doctor Phil said with obviously feigned interest.
Within a minute of that event, ratings on the Doctor Phil show jumped 35%. They rose steadily for the remainder of the show but in the end that seemed to be that...
...Until two days later when every major newspaper in America ran front page stories on how that seemingly innocuous event had caught on and how sun-glasses had changed, overnight, the way people deal with each other. Schools were thrown into chaos as children donned shades during classes they didn't like. Members of the senate showed their disapproval by putting their sunglasses on. Resolutions and laws were passed by counting the number of sunglasses in view in the senate house. Divorce rates plummeted as husbands and wives could now communicate a little bit more effectively. This conversation was heard countless times around the country:
"Is there something wrong, hon?"
"Oh, come on. You've been acting down all day. Tell me what's wrong."
"I said there's nothing wrong."
"But you're wearing your sunglasses..."
"Oh, I guess I am... well, actually, there is something wrong. I know you slept with my sister."
The demand for sunglass materials jumped massively and the mineral compound lytblokium became the most valuable mineral on earth as manufacturers crawled over each others rotting corpses to get their hands on some. The entire country of Egypt became a single monolithic sunglass manufacturing plant.
Referees wore sunglasses whenever players started bawling at them. Mother wore sunglasses whenever their children starting bawling at them. Businessmen wore sunglasses whenever their investors started bawling at them. Nobody listened to anyone, and if anyone started to bemoan this fact they quickly discovered that everyone around them was, all of a sudden, wearing sunglasses.
Road traffic accidents shot up by 740% as drivers wore their sunglasses at night. Insurance companies donned their glasses whenever the drivers called them up. Doctors wore sunglasses the whole time.
And then all of a sudden, a strange thing happened. People stopped getting sick. Apart from the occasional illness here and there, disease started to fade from the minds of the people. And that wasn't all. People started to live longer, and were happier. The ability to avoid stress in all its forms by putting on a pair of sunglasses transformed the direction of society, as we know it. War, too, faded into distant memory, as people stopped giving a fuck about what their neighbouring countries were doing and simply got on with enjoying the good bits of their lives and ignoring everything else.