Where do you turn when you’re heartbroken in the dead of night? Delilah, of course. Her radio call-in show pairs romantic advice with the perfect song. Plus, how Yanni, John Tesh and others discovered an improbable vehicle to ‘90s stardom: the PBS pledge drive. For our Guilty Pleasures series, the writer and “This American Life” producer Bim Adewunmi explains how the “Sweet Valley High” series is kind of preposterous and over-the-top — and completely obsessed her.