Talked about a piece of software I developed and deployed as a side project whilst at a company. The software automated some of our tasks but was not liked by a manager. I had to tell my colleges not to use it and the project was a waste of time and rather publicly an embarrassment. I learned that I needed to check with stakeholders (the manager) before beginning to implement an idea in code to make sure the software will be useful when complete. I was met with a snide remark that this was not embarrassing or a failure in my interviewers eyes (which confused me).