Harry, despite your privileged insight into Voldemort’s world (which, incidentally, is a gift any Death Eater would kill to have), you have never been seduced by the Dark Arts, never, even for a second, shown the slightest desire to become one of Voldemort’s followers!” “Of course I haven’t!” said Harry indignantly. “He killed my mum and dad!” “You are protected, in short, by your ability to love!” said Dumbledore loudly.
J. K. RowlingDepression is the most unpleasant thing I have ever experienced. . . . It is that absence of being able to envisage that you will ever be cheerful again. The absence of hope. That very deadened feeling, which is so very different from feeling sad. Sad hurts but it's a healthy feeling. It is a necessary thing to feel. Depression is very different.
J. K. Rowling