Obamacare patients are discovering that many doctors, hospitals, and top cancer centers do not accept the plans they purchased. "It's so frustrating," Terri Durheim of Enid, Okla.,told CNN. "It's not doing me a lot of good." Durheim is not alone. Obamacare's so-called "narrow networks" are designed to limit customer choices to push patients into cheaper choices in an effort to control costs. Earlier this year Washington Post health writer Sarah Kliffwarned that "Obamacare's narrow networks are going to make people furious – but they might control costs." A McKinsey and Co. study finds that more than one in three (38%) Obamacare plans permit patients to select...