@thegibson The first time I sent code upstream as part of a job, it didn't even occur to me to think of whether the variable names might be leaking information about other stuff we were working on. I had the good fortune to have a boss who believes in teachable moments, however.

Deleting all of /usr due to a typo.

Long ago, while I was working on some PHP and SQL while knowing nothing about SQL, someone asked me to add group permissions. So I added a 'group' table containing one prime number per group, and the permissions field on resources or the membership field on a user was just the product of all the relevant groups.

Probably the worst mistake I've ever made in any domain was when I was having psychiatric issues and insisted, against everyone's advice, that I had to jump back in to the thick of things right then and there to restore my honor instead of stepping back and taking a few months to sort things out.