I made the mistake of mentioning my day-job requires a lot of mental energy and this job would be less mental and more physical. A welcomed change. I believe this answer was my downfall. The interviewer admitted this job did not require high-level thinking/reasoning but nevertheless I am sure I offended him, and I felt bad because I did not mean to. For those thinking I'm arrogant, the interviewer asked me explicitly why as a software developer I was interested in stocking shelves on the nightshift. At the time I could use the extra money, exercise, and change of scenery. I've worked retail and food-service but never grocery.