When Buffy dies at the end of The Gift she doesn't go to heaven or hell.  Instead her ghostly ass gets chained to Spike.  He can't see or hear her, but she witnesses everything he does.  She sees his near suicidal misery and Dawn's concern for him.  She sees him slowly pull himself together, but only because Dawn needs him.  Through Spike's interaction with the Scoobies, Buffy sees how Tara becomes a maternal figure for Dawn while the others are lost in their grief.  Spike becomes a surrogate big brother who teaches Dawn things that Buffy feels are completely inappropriate such as cheating at poker, picking locks, hotwiring a car, pool hustling, how to threaten a handsy boy with a switchblade.  As the summer progresses she realizes that in his own twisted way, Spike is trying to teach Dawn to survive.

When Buffy is resurrected she isn't apathetic or angry because she wasn't in heaven, but she does see Spike in a new light.  After spending 147 days entirely in his company, she finds herself craving his presence and a relationship grows between them.  The scoobies react terribly and it comes to a head when she admits to being a ghost and seeing how much Dawn was pushed off onto Spike and how he cared for her.

I'd like to see Dawn being 'adopted' by a small part of the demon community, IE Spike's poker buddies.

An interlude just before Buffy gets resurrected where Spike tries to be intimate with a female demon but ends up breaking down entirely.  The woman, knowing Spike was in love with the slayer (I can only imagine something like that would be huge gossip in Sunnydale) is sympathetic.  A slightly jealous, but repressing Buffy who is witnessing the entire event finally comes to the conclusion that demons really can love, because the depth of his despair wouldn't be possible otherwise.