"On the plus side, all of our feces is organic and locally shat."
Because guess what -- that cart hasn't been cleaned in a while, if ever. Think about it: When's the last time you've seen employees at your local grocery store hosing down the carts? Never, because it's just not part of the program. It'd be a losing battle anyway, when you consider how many people use the cart in a day, and how many nooks and crannies there are for all sorts of microscopic bullshit to thrive in.
"But Cracked," you reasonably inquire, "what about the sanitizing wipes most stores have right next to the shopping carts? Surely those can be used to clean away all that crap." They can help, sure enough -- if you're willing to take 20 minutes per shopping trip to thoroughly wipe every inch of a device that is essentially a wheeled basket made of tiny secret microbe lairs. But even then, the only way to get them really clean would be to spray them with a cloud of disinfectant, or maybe run them through a car wash or something, after every use. But nobody does that, so poop carts it is!
This girl alone is responsible for two elderly deaths, one ruined honeymoon, and 35 cases of pinkeye.