I wrote a random password generator once. I was a naive young developer, and I thought it was helpful to generate memorable passwords, so I threw a dictionary of words into it without really checking the content, beyond the obvious swearwords. First day in production, it generated an inappropriate password and suggested it to a user.

When I replaced it with a different non-word based alphanumeric algorithm that couldn't issue someone a password of 'fat cow 392' ever again, I considered that a 'safe' implementation.