For example, I’m using Debian, and I think we could learn a thing or two from Mint about how to make it “friendlier” for new users. I often see Mint recommended to new users, but rarely Debian, which has a goal to be “the universal operating system”.
I also think we could learn website design from… looks at notes …everyone else.
For me it’s mostly that the site sprawls in unintuitive ways. It’s possible to have a simple look while being easy to navigate, for example (and this is subjective, but still) https://www.openbsd.org/