I use lights every day, but I know way less about electricity than my grandparents, two of whom who could remember when their town was electrified as children and who therefore treated it as the marvel it truly is. And also because we've worked out a ton of bugs in electricity and it often just works.

My kids will know way less about filesystems than I do, because I had to learn DOS commands to navigate around the operating system if I wanted to play computer games, which led to a lifelong interest in how computers actually work at a level they can (and, so far, do) happily ignore.

Or in your scenario, understand the concept of 8.3 file names and why they existed, and when they were removed, and how :P