Angst of science.

I get this terrible sinking feeling when I discover an error in my calculations, because it means there are probably more, and I might have to do a lot of analysis and writing over again, and frankly checking calculations for errors often takes longer than just doing it over. When I shortly thereafter discover that my original math was correct, and I was just having a brain fart, this does not greatly improve my confidence in my other calculations, so I go through and recheck everything else I've done. But part way through that, I realize there would have been a much more convincing way to design the analyses, so I do that, which takes all of today.