There was a system I was a user on once a long time ago, user being important, where I got into the habit of running kill -9 -1 to literally (SIG)KILL all processes to log out. It meant I didn't leave anything running and I had already saved my work. Never had a problem with it. It only killed processes my account had access to, after all.
Later I used it to log out of a system I was root on.
root. oh no.
There was no grinding and crunching of gears, but my brain plays that sound effect anyway.
Thus the habit was very quickly unlearned.