On Casual Fridays

Not too long ago, I was hanging out with my grandparents and I don't know exactly how this came up, but my grandpa claimed to have invented the concept of Casual Friday. He said that when he was working a long time ago (possibly at Standard Oil), he "didn't feel like wearing a tie to work" on a Friday. Apparently, others agreed with him and the following week, more guys were showing up to work without ties. My grandpa told us that after that, the bosses said that no one had to wear a tie on Friday.