oh man, I'm thinking of ideas here. say...
the "afterlife" is really just a holding pen for people who were reluctant to die, who died expectantly, or who just weren't ready (so the population of seniors is low, car accident victims high). Once they come to grips with their death, they fade away and just stop existing, which is supposed to be a form of peace since 'heaven' really isn't all that great. You just walk around and stuff, with no needs. (there could be forests

) If you jump off a cliff, you can barely feel pain, and the only emotion you can really feel is the emotion of "okay, I'm ready to go now."
Enter MC, a girl, who's just died. She walks around, contemplating her death, and meets with a boy who's just died... they like each other, but they can't fall in love because of the diluted emotions. This is a problem. Neither of them wants to 'fade away' because they each have important ties to Earth (to be thought of later). So together they work to start feeling emotions... to start feeling pain... putting themselves in incredibly dangerous situations just for that single spark of feeling. Finally, they succeed, and they fall in love or something close to it (and mebbe make out a lot? or just a lil?). So now they have clear heads, and they realize how much better it is and that everyone around them who fades away in matter of days is being stupid. And so... um... something happens, and something else happens, and there are subplots, and in the end they actually return to Earth. as ghosts. but a new kind of ghost. and then there's a sequel.
LOL
ETA: THE BOY could be the boy WHO DIES in my current WIP *gasp!*
I swear to god, I don't actually think about death that much. I barely think about it at all. It's just a crazy interesting and beautiful plot device.