My uncle (a sheep farmer) and I discovered that:
1. I was afraid to touch anything in a car engine, but happy to muddle through unfamiliar computer issues
2. He was afraid to click unknown buttons on a computer screen, but comfortable pulling apart and rebuilding an unfamiliar car engine.
In both cases, we were confident because we knew whatever mistake we made we'd be able to reverse it. And in both cases, we were afraid of making a mistake that we couldn't reverse.