Same here (writing this at 4am, having been awake since 2am). I hate the feeling of having made a dumb mistake. Sometimes these are not easily addressed without stress and financial penalty. There is the feeling that "I should have known better. I DID know better. But somehow it happened anyway." Some people would call this perfectionism, and say that we are too hard on ourselves. And they are right of course. But we don't see it that way. We see it as "the whole world will think we are stupid." And our self confidence drops down into the gutter. All I can say is that I expect that in a year's time you'll probably barely remember that wrong job. Plus, in the pecking order of bad decisions, where people have died because of bad decisions, a mistake costing a few thousand dollars is pretty small-time.
