Ask HN: What is the most unethical thing you've done as a programmer? 8 years ago
Ran an illegal live streaming site for a few months. Had a lot of fun with it and used the experience to transition to a legitimate job in that space, but I probably cost some people some money, and for no other reason than "I could".
I also worked at a startup briefly that was run by a convicted con man. The business was legit but it was immediately clear he was using the same confidence techniques on everyone - clients, employees, etc. Not a good scene.