The first interview was very typical and was used to get to know myself as the candidate and the interviewer.
After that, there was a case study. To move onto the next steps, the case study had to be completed. The case study was a bunch of nonsense data, and I put a lot of effort into it. I did appreciate that it was fake data and that the company was not looking for free work through case studies.
After the case study, there was a panel interview. This was the worst part. This panel interview was not at all about the job, the work, the project, or the duties of the position. Instead, it was an investigation into my personal beliefs and life. The interviewers here very much liked to hear themselves talk. I was asked absolutely ridiculous questions, such as, "What is your personal optimization function?", and my personal favorite, "What makes you happy?" One interviewer in particular was grilling me about my personal beliefs and morals and my opinions on the ethics of marketing. This would have been a tech role. The interview ended with the interviewer implying that I would have been too morally soft for a role with this company. After this, I was rejected.
Many months later, the team did respond to see if I was still interested in the position. I declined.