The answer may surprise you.
Then again, maybe it won't. Hopefully, by this point, you've heard that plastic bags are a huge issue for recyclers. Try this test at home: twist a plastic bag until it becomes like rope, then try to break it. Surprisingly strong, no? Plastic bags and other types of plastic film get clogged in the sorting machinery that separates all the paper products from the containers.
When the machinery gets clogged, it has to be shut down and cleaned by hand, as seen in the photo below. How often would you guess this cleaning takes place? Once a week? Once a day? How about every two hours. This cleaning accounts for more than a quarter of labor costs at sorting facilities such as the one in Clark County. If you only care about one thing when it comes to your recycling cart, let it be this. Your recycling handler and your planet thank you.