I had that same epiphany when reading a biography of Ernest Hemingway.
Another type of work I avoid are "the making of ..." documentaries/accounts of classic works of film, music, and TV shows. Pulling back the curtain really destroys the magic.
>>ilamon+(OP)
I had this same feeling. Same with reading a biography of Kurt Vonnegut. Before reading it, I thought of them in idealistic ways. They had multiple affairs and weren't such great people, even though they both wrote really, really well.