A little bit of feeling guilty is in order; the author "didn't know that he didn't know", and I'm sure this motivated him to learn a lot more about proper engineering processes ... something I'll note aren't particularly a focus in CS degrees. Especially since I haven't come across anyone who's really dedicated to them who hadn't first gotten burned in one way or another.

There's a big difference between being told "Do X, don't do Y" and that sinking feeling you get when you realize a big problem exists, regardless of the eventual outcome.