We recently got a junior-dev straight out of finishing his CS degree. And he didn't know you could "extend" your desktop and show different things on each side by plugging in a monitor. When quizzed, he told me he's "always just had a laptop", and never a monitor next to it I assume. He was then equally perplexed by the resolution and corresponding font-size change that occurred on the monitor because it could now run its own native resolution rather than what the laptop screen was forcing it to mirror.
I think there is something to be said for what classes don't teach you. You can ace a test but have very little practically knowledge if you don't work with stuff outside of class. I honestly think that you learn 10-50x more in practical knowledge from the organizations that you can join in college than the classes themselves.
It was quite eye-opening to see that.