I can't speak for Amazon but I had an order picking job at a Volvo warehouse in college, and despite having to hit a certain number of picked items every day it

I can't speak for Amazon but I had an order picking job at a Volvo warehouse in college, and despite having to hit a certain number of picked items every day it was oddly relaxing. Once you got good at it you could zoom through your day on auto pilot. Drive to aisle X, pick up N boxes at rack Y, rinse and repeat.