The first production outage of my sysadmin career was when I crashed a university email system at a summer camp (I was a kid attending, probably very early 1990s?) by circumventing the block on emailing the entire university, using the Mac keyboard shortcut Cmd-A to select all in the recipient field in the cc:Mail UI. I apologized for childishly causing harm with something I thought would be funny, and so they decided not to kick me out.