Don't let the interviewer reflect too much on your decision. Given the fact that they interview every single one of their applicants, there are going to be serious inconsistencies between personalities. We are evaluating NU as an intitution after all - and the truth is that 1 meeting with an unpleasant person should not be representative of the entire institution. Now if we go to admitted students weekend and everyone is a jerk - thats a different story. My two cents.
I can't help but think that the admissions people are getting pretty tired of doing interviews at this point, whereas those of us who did it off campus probably met with people who do a half-dozen or so during the entire year. Between all the interviews they've already done and dealing with phone calls from hundreds of anxious applicants, it's probably hard to maintain enthusiasm.If you interviewed with a CPA in early April, you'd get the same thing. Don't take it personally or assume it will impact your chances. Good luck!