My personal most difficult question was actually on the written test to qualify for interviews, and then the followup in the interviews. They wanted to know about my experience administering a defined-benefits retirement plan (gotta love State employment). I sorta have experience there, but not at the level of making recommendations for what those defined benefits should be. All my experience was how to apply for and get all those defined benefits out of Uncle Sam, which isn't exactly what they were looking for.
