It’s always refreshing to have a “lightbulb moment” every once in a while. You know the feeling, you’ve been working with some system or on some problem for hours (or weeks or months) and you suddenly find that one piece of information that makes the whole thing fall together and make sense. It’s usually a satisfying feeling.

It’s less satisfying when the lightbulb that comes on is shining very brightly on a bad assumption you made at the outset.