When I was younger and dumber, I did two full day interviews at Amazon, 9am till 4-5pm. No lunch, no bathroom breaks, wall to wall interviews completely unrelated to the initial reasons for my contact. Actually rude to the recruiter after the first day, I was convinced to return for a 2nd round of interviews. I never bothered to return any contacts after that incredibly poor and redundant treatment. The exact same thing happened on the 2nd day: no lunch, no bathroom breaks, tons of waiting, and unrelated interviewers.