I've seem to have noticed more of my Amazon deliveries being carried by USPS.

Which I wouldn't have any issue with, but I've had the experience that USPS postal carriers are, well, less physically able to handle large packages. We order both Amazon Pantry and Subscribe & Save items, meaning we have 40lb boxes of dog food or cat litter coming in, sometimes several times per month.

I get a complaint almost every time from the postal carrier. I don't necessarily blame them, especially when Amazon puts 80lb of goods in one box. At the same time though, I end up feeling guilty just for ordering these types of items online.