If I wasn't interested in the work, than it's just a means to an end. I must not occupy my mind, because whatever I'm doing after stacking shelves is what will occupy my time.

Given in this scenario, programming being equally unrewarding, I wouldn't be doing either. Period. I don't find programming itself rewarding either, it's also a means to an end in a way. I'm not a programming and never have been professionally. It's a tool to satisfy my need to build things.

I may be arrogant, but like many, I believe I was put on this earth for more than sitting at a desk, or stocking shelves, but I'm not above either. That said.

if both are equally unrewarding, and have the same social/economic status, then it comes down to more simple things i think. Id rather work with my hands and have my brain idle for the work after my job. I'm not a desk person, and I don't like building other people's things. It's that simple.