I went through 7 interview stages which also included a verbal case study, panel interview, and a case study presentation. I received glowing reviews from everyone. After the final round, they added on an extra interview which was not pre-planned for me to speak to some leader from a different organization function in which I would not be reporting. This guy acted like the devil himself in this interview, and I still think I did a good job. For whatever reason, I was not extended the opportunity.
I really believe they had no intentions in filling the role, and used me for free consulting work. It wasn't until after this experience, I realized that this was a big thing for many organizations. I have never felt so used in my life.