GLG interview questions

I applied online via their website with a resume and cover letter in November. I did not hear back from them until late January. When they contacted me, I was asked to set up a date for two 30 minute phone interviews. The interviewers were low-level employees, but they were kind and seemed like they wanted the best out of me. I did not feel that they were trying to break me down or find weaknesses. They did not ask any unexpected questions, but mostly focused on making sure I understood the role I was applying for. Information I learned in the first conversation actually helped me in the second. After about a week, I received an email with a case-study and they gave me three days to return it completed. I returned it on the third day and received an email to set up a 30 minute phone interview discussing the case study. This was the most difficult part of the entire process. He asked very specific questions, to several of which I could give no decent answer. After a few days, I was contacted to select a date for a series of three final video interviews with high level employees (Two vice presidents and a senior manager). Again, I felt like everyone was on my side, but these were much tougher questions. They weren't out to get me, but they wanted to see how I think. Honestly, these were some of my favorite interviews I ever had. I learned a great deal in the process.