You’d never guess it from the yuk-a-minute CBS promos, but Mom, the Anna Faris/Allison Janney sitcom that begins its second season Monday, is a show about alcoholism. No, it’s not about characters who drink constantly and hilariously (that would be Cougar Town). On Mom, single mother Christy Plunkett and her mother Bonnie never touch the stuff. But each week, everything they do is framed against the background of their drunken pasts, and their weary, grudging attempts to make the future better.…  [more]