Hey, hey, "do you want to know why I smile all the time? ...'cause it's worth it." - Marcel the Shell.
But really, it took me a long time to learn that one of the more positive aspects/options we have in life is our generosity. If we share something, something that costs us nothing, like a smile, and the person doesn't return the favor I'm the dick that walks away whistling and imagining how fuckin' shitty that persons life is that they can't even accept such a small token of humanity. Then I picture them going home all alone and unwrapping their freezer burned microwave dinner while they talk to their miserable declawed house cat. Then they get in the tub and cry a little while running that razor across their skin. I think all that and keep whistling and smiling because fuck them, I don't have no nasty cat and I own a gun to commit suicide. Like a normal fucking person.