Three years ago, I was sent as a consultant to help a struggling small, local health insurance agency. They had a three man team, the lead had been there for fifteen or twenty years (built their system). He assured me on the first day that they didn't really have any bugs and that the system was pretty stable.

We were called in to help them because their management (and users) were aware they were underwater with the amount of bug fixes, live production data changes they made to keep things working, and impossibility of adding anything new to the system without tipping something else over.

It seems the attitude that "there's no chance we have any bugs" is pretty prevalent anywhere I've ever been, along with the usual mix of "how did this ever work" which I still always find pretty shocking to run across.