del *.*
del *.* in the root directory in the days of MS-DOS is the worst I ever did. On a colleagues PC at that! Easily fixed though, after a few moments of heart stopping panic. His autoexec.bat and config.sys were pretty much factory default and del *.* only deleted the files in root, not directories and as per normal practices, there was barely anything in root in terms of files.
Biting the hand that feeds IT
