The worst thing that ever happened to me with computers -
Years ago (1995) I was administrator of a Novell NetWare system. At that time, all the login scripts were held as a single file, with "if username=nnnn then do" statements. Not my idea - someone else's bright idea, considering there were about 450 people on this system, over multiple servers (I seem to recall that each server had a 250 user license, and there was much duplication of accounts to access shared information).
Anyhow, while working on the system in building B, with the server in building A, the network link went down - while I was editing the syslogin file (I can't actually remember the file name now, it is over 10 years since I last used NetWare!).
Imagine my horror when I got back onto the server to discover that the syslogin file was now blank...
For some reason that I have now forgotten, the backup tapes were unusable also.
That was a real "kicked in the nuts by computers" day.
SD