North America's largest trash hauler has had a rough year. Should long-term investors be upset?WM (WM +1.30%) is the top trash hauler and landfill operator in North America, but that doesn't necessarily mean its stock is a top performer. And if it isn't, aren't investors almost obligated to make plenty of "trash" jokes about its performance?Here's how the company, formerly known as Waste Management, has been doing for investors recently, and what it tells potential investors about this industrial stalwart. ...