Ward Christensen taught me the joy of hacking, just modifying things to suit my will. He once told me that he heard "You can't write programs in assembler for OS/2" at work at IBM. With his help getting me the C++ compiler kit, this challenge resulted in Forth/2, a direct threaded forth for OS/2, written in assembler, of course.
Russel Reynolds taught me the nature of software development. He was the Operations Manager at Will County Generating Station, which burned coal and turned it into power. He saw computers as a tool, and one that had to be as practical and unobstructive as possible. In the 1980s, he sought out hand-held computers for recording the inspections of fire fighting equipment. He tried running them with gloves on, spilling coffee on them, dropping them on the concrete floor. I wrote the software to record the inspections. He'd pull in a person from the staff, back in the day when most people didn't have computers, and explain to them that They weren't being judged, I was, and if anything went wrong it was MY fault, he then told them what he wanted them to do, and I had to watch. I learn huge amounts about software usability in a very compressed timeframe.
Jack Woermbke taught me that you don't every upgrade software unless you actually have to. He taught me you only change one thing at a time, so you can actually know what broke things, or fixed them.
The folks at Live Marketing taught me how tradeshows work, how marketing works, and how to keep folks who have to use computers happy and productive.
Norman Teiber taught me how to make gears, and gear shaped objects, of all sorts at his job shop, Allied Gear, sold in 2019.
My friend Jim has shown me how to repair old radios, test equipment, and the like. We've repaired TVs from the 1940s, Test Equipment and ham radios of all vintages, and even a few Cesium Beam atomic clocks.
Jim Hoover from Fermilab taught me that the world isn't as it seems, you can't just take the news at face value, back in the early 1990s.