That said, I've never been even remotely tempted to move to anything besides Emacs, and at this point, it's ingrained in my fingers, so non-Emacs things really piss me off.
I'm just glad that C-x doesn't quit most applications while I'm trying to save.
I know there are alternatives like It's All Text extension [1] which lets me hook emacs into Firefox, but it's not been updated for recent versions of Firefox.
[1] https://addons.mozilla.org/en-US/firefox/addon/its-all-text/
There's conkeror that use the same renderer engine of Firefox but with emacs mentality of keybindings and customisability.
Also, I've read that some people like to rebind their ctrl+W to something else so they don't have the habit to close their windows in other os/apps. IIRC, C-w is kill-region? Personally, as stated earlier, I use evil so I don't have that problem (I press d to delete the selected region).