When I double shift and work the unload during twilight, I loath Amazon trailers. They usually use the really long 50-something foot trailers (I think), and the extendos do not reach nearly that far. You're forced to extend it by attaching rollers to the end, and the rollers we have suck balls. The gaps between each individual roller is just wide enough for the edges of small boxes to get stuck in. Half of what you put on the rollers ends up falling off before reaching the extendo (slight exaggeration).
The nose of the trailers are typically bricked with boxes, floor to ceiling. On the rare occasion, the walls will be put together very well. Most of the time it's a complete mess. The walls tend to shift and lean back towards you, which results in many box avalanches. I've had the honor of being under one of those avalanches as it came falling on my head, knocking off my glasses and crushing the frame.