Phone screening is fairly aggressive, like making an attempt to demonstrate you're just not worthy of being there. That kind of attitude permeated the on-site interviewing as well. The "test" portion is mostly an effort to show that you could be joining this elite club, but only if you prove your worth. It came off as a bit intimidating and arrogant, but not insufferably so. Try to read through the sample questions on Business Insider and elsewhere on the web to get a sense of the problem-solving type questions you are going to face. While there might not be "wrong answers" to some of the open-ended problems, there is definitely an ability to shine or fizzle when you get the floor.