This was a LONG time ago and I was a real newbie to PCs being primarily a Mac tech. But a big Pharma company in NJ was migrating from WIN 3.1 to Win 95.
Our instructions were to boot from our special network boot floppy, CD to the C: drive and delete everything on the drive with your standard DOS command to do so.
I had done a dozen of these with no problems till one where I forgot to CD to the C: drive. Seems the floppy left your current directory as the network drive that held the install files that you were supposed to just copy to C and then reboot to run.
I think you can see this one coming. I neglected to change directory before issuing "DEL STAR DOT STAR" and the brilliant sysadmin who had set it up made that share R/W to EVERYONE and bang away goes all of the files that were needed by about 30 techs swarming over the building trying to get several hundred PCs upgraded over the weekend.
And to make matters worse, they had no backup.
So everyone went home with no idea of who did this grumbling about lost overtime. And a few SysAdmins grumbling about having to rebuild the install share from scratch.
Needless to say I was "busy" next weekend when they tried again.