My dad was a relatively early adopter of synthetic, specifically Mobil 1. He worked as an instrument and controls technician, and his job was caring for all of the instrumentation and control equipment in a coal fired power plant. They had many conveyors to move the coal, and the conveyors were obviously driven by large electric motors coupled to large worm gear reducers.
A Mobil 1 sales guy called on him, and what was ultimately his best pitch was offering to replace the gear oil in a couple of reducers for free as an experiment. Everyone in the plant knew you didn't dare touch a reducer after it had been running for awhile, because they got really hot. After replacing the lube with M1's gear oil and turning the conveyor on, the salesman dared my Dad to touch the reducer. He smiled knowingly at the salesman and said: "You first." The salesman laid his whole hand on top of the reducer and kept it there. After checking to be sure the salesman didn't have some kind of unseen protection, Dad indeed laid his hand on the reducer, and was amazed - and SOLD.
Dad also switched to M1 for his vehicles, and used it exclusively for many years.