Fess up. You know it was you.
I didn’t call out a specific dimension on a machined part; instead I left it to the machinist to understand and figure out what needed to be done without explicitly making it clear.
That part was a 2 ton forging with two layers of explosion-bonded cladding on one side. The machinist faced all the way through a cladding layer before realizing something was off.
The replacement had a 6 month lead time.
One time I was deleting a user from our MySQL-backed RADIUS database.
DELETE * FROM PASSWORDS;
And yeah, if you don’t have a WHERE clause? It just deletes everything. About 60,000 records for a decent-sized ISP.
That afternoon really, really sucked. We had only ad-hoc backups. It was not a well-run business.
Now when I interview sysadmins (or these days devops), I always ask about their worst cock-up. It tells you a lot about a candidate.
I worked for a company where the testing database was also the only backup.
Then colleague upgraded glibc by copying it in via scp. Then we couldn’t ssh in anymore. :) Not sure how important that server was. I think it was reinstalled soon-ish.