In a few apps on the Mac I have made good use of the Keyboard Shortcuts part of System Preferences to prevent this. If destructive behavior is a bit too "easy"

In a few apps on the Mac I have made good use of the Keyboard Shortcuts part of System Preferences to prevent this. If destructive behavior is a bit too "easy" in an app, I remap the command to something complex. I think my Quit in Firefox for instance is now command-shift-control-Q or something.