I was on the hook with recruiting and the hiring manager for 3 months before the role was ready for interview. Standard interview of culture fit, systems design, iOS knowledge test, and a live coding exercise. This occurred over the course of four hours, ending at nearly 9pm on the east coast with just one brief break after the first of the four sessions. The live coding challenge was to build a simple JSON parsing app that would display and sort content. I was explicitly told to go ahead with "anything you'd use day to day" at this part by recruiting and the interviewer. Being a tenured engineer for a legacy codebase, I hadn't bootstrapped a new project in a minute and went to Google for a refresh on standing up some models with Codable. The interviewer became agitated and warned that using Google wasn't "appropriate" for the interview. I was stunned after being told to use whatever I do in my everyday. Still, I stumbled and managed to get most of the project working but not finished in the timeframe. I sent a thank you note with feedback on the interview that they'd asked for since they were rethinking how it's run anyway. I also took a few minutes to correct the mistakes I made in the exercise and sent over the finished project. The rest of the team apparently loved me but the coding exercise left such a bad taste in the mouth of the one interviewer that she wouldn't budge, so no offer. To this day, it stands out as my most negative interview experience of my career. Such a long process just to be nixed over conflicting instructions.