I didn't start developing code on *nix systems until around 1987. At the time, I was doing a gig with BBN, which a former coworker described as “a halfway house for MIT postgrads.” As such, emacs was clearly the editor of choice, although we used Sun hardware, so vi was available.
On my first day, I sat down with the emacs tutorial. And after a few minutes, tried to save my file. Nothing happened. In fact, nothing I typed had any effect. It took me a few more minutes to figure out what had happened.
I was using a VT-100-compatible terminal (I can't remember the name, but it was a very nice machine with a rotating display that would either show 48 rows or 120 columns). And a VT-100, like all of the ASCII-based terminals that preceded it, used Ctrl-S and Ctrl-Q to suspend and enable the flow of data.
Emacs uses Ctrl-X Ctrl-S to save a file.
My coworkers tried to convince me that this was not a problem: “just remap your keyboard.” But I decided that any editor that could not be used, as-is, on the world's most popular computer terminal was the product of a design ethos that I wanted nothing to do with. I switched to vi and haven't looked back.