I took some forklift training when I was in Illinois. I have a lot of respect for guys that drive those all day. I got nervous past the second row, and generally left the restocking to someone else.
At my first job out of high school, I worked in a photochemical packaging plant. They used to stack the bins of finished liquids 20 ft. high. One day, a forklift driver missed on picking up the top bin (4 layers high), and couldn't move without dropping the load. A second forklift came over, and they managed to put the bin back on the slots without dropping everything.