I have a book on my shelf that I occasionally read to make myself sad. It's Birds of America by Lorrie Moore, and I picked it up at a secondhand bookstore because it was cheap.
It does not contain the heart-wrenching and dramatic sadness of death and loss. It never actually brings any tears to my eyes. Instead, it produces a general sort of disquiet that stays with me for days. It's the sadness of Eleanor Rigby and Mad World. It's the sadness of abandoned homes. It's the sadness that keeps me from hanging around the deli section of the grocery store, near the piles of boiled eggs that no one will buy. It's the sadness of toy stores that no one visits, and puppies that are alone in their cages, and biographies that don't sell, and empty Chinese restaurants. On their own they're just buildings and books and puppies and eggs; it is only when framed in a certain context that they become sad.
I think, though it's hard to put my finger on it exactly, that it's the sadness of loneliness. Things that are left behind, or unwanted, or misunderstood, or that were once treasured and now are not. Moore's stories are about people who are stuck in unhappy lives, without the power to affect change or even identify exactly what is making them unhappy. There's one line that has always stayed with me: his young, sad wife. To me, it's more poignant and heart-wrenching than loss. Maybe it's because I've lived my life being familiar with that very same quiet unhappiness, while the grief of death is entirely strange to me. It's not necessarily that I identify with these characters, but more that I know people like this exist, everywhere, and that's a deeply upsetting thought.