Easily the most difficult interview I've had. The interviewer was thorough and wanted many details of each position I worked and how they were complex. Complex really is the key word here. This isn't an interview where you're asked a few general questions and the company can get a feel for your values and why you want to work there. They want to know how you are analytical, and you must give them details. They want you to break down complex topics because that's what the job entails.