The Wednesday after I got back from Chicago, I had planned to have an easy workday. Get in, work on my latest story-ticket, nice lunch, home early, all that jazz.
A coworker was demoing a story to the lead and the system threw a nice big juicy bug, putting an end to that plan. The code that worked just perfectly when I ran it locally just horked up a lung and died when it was on the test box.
Not ACTUAL bug, computer bug. Still, horrible.
Said coworker enlisted my help, because they had no earthly idea what it could be.
After a while of banging my face against it, I figured out why it woiuldn't show on dev, but did appear in test, and exactly what was causing it! (If you really want to know why and what it was.. the why was because of differences in the dataset and the what was that datatables.js doesn't support colspan attributes in tables. Having one causes the HTML to be considered malformed by the library. This can be easily fixed on a .gsp by swapping out the HTML in question conditionally, using a template. See, you didn't really want to know, now did you?)
Anyhow, it feels good to figure that kind of stuff out.