I had an interview at a startup years ago (got the job) that was grueling, about six hours total, you met with six different teams of three people, from different disciplines across the company. It was sort of a good cop/bad cop thing. Not to aggressive, but just seeing if you were willing to admit you didn't know when you were asked a questions you didn't know (and there were lots I didn't know) and how you reacted in the situation. Some people don't handle 'not knowing', and try to BS their way through. Then, some are apologetic when they get called out, and some dig in. If you fell into that last group, you were not getting a job. If you fell into the second group, it was more of a sliding scale. Did you attempt to BS your way through multiple times across the multiple teams? Or did you realize, the first time you got called out, that it wouldn't work.