I've spent time at Amazon, I suspect:
- Amazon persistently strives for efficiency and frugality over all else: applies in FC and HQs. I think this culture could turn off many people
- Kiva will reduce human usage/energy (not sure if that's where you were headed though)
- Inevitably, optimization means reducing the cost (inc human effort) required to store and fulfill products
- Having visited FCs, the ones I saw had fine working conditions though I understand the reality of publicity in the past
