Early in my career (a long time ago), I was tasked with ordering replacement chargers for some laptops. I ordered several off Amazon and even though they were labeled as being what we wanted, they were apparently bootleg and were not, in fact, the correct charger. Fried a few laptops before I realized Amazon wasn’t the “Amazon” of yore selling first-party parts and I was ordering from random third party sellers. (That was all relatively new at the time. Amazon was a bookstore branching out in my head.)

In fairness, I was a programmer and not an electrical engineer. And chargers back then weren’t exactly USB-C level smart. The barrel charger fit. I just thought “Oh, what a great deal. I’ll order these and get plaudits from my boss for saving money.” It wasn’t even my money.

The other one is that when I was learning to code — I’m self-taught because everyone was back then — I used Vim and invented my own style. All my code was basically unformatted or, at best formatted consistently in a very non-standard way. That’s easy to fix nowadays where I can hit save and my code gets formatted automatically but it wasn’t so simple back then. I still feel bad for the engineer who followed me who had to fix that shit.