I use nano when I need to edit something from CLI because I don't like ancient editors with modes or non-standard key combinations from 80s. And in nano the most important shortcuts are at least written in the bottom of screen.

While nano supports some standard shortcuts (arrows, Ctrl + arrows, Home, End, PgUp, PgDn), others are non-standard and I don't understand why. For example, "save" is Ctrl + O instead of common Ctrl + S, exit is "Ctrl + X" instead of "Ctrl + Q", Esc doesn't work when you want to cancel search, and so on. What a nonsense. Why should someone use different shortcuts for the same function.