Two guys, walking through a graveyard.
"You're lucky to see the back of her, mate. If she really loved you, she'd've loved you geek and all. 'Course, that's asking a lot of the poor girl."
"Yea, though I walk through the valley of the Shadow of Death, I will fear no evil--and sadly, I will be unable to make it shut the hell up."
"Just trying to help."
"How does making me feel crappier help me?"
"Oh, doesn't help you. Helps keep me amused, though."
"I'm so glad we're patrol buddies. If I were alone, I'd have to flagellate myself."
"Flagellation's a bad habit for a young man to fall into. But I understand. You're alone, girl gone--"
"Okay, I don't know what you're picturing but--stop!"
"Don't worry. I can keep a dirty little secret."
Spike was watching a documentary on honey badgers. He got excited when the badger climbed the tree and bested the angry cobra. He cried when the little badger cub was mauled.
He felt love as if were something ineffable expressed in physical form. He used to think these feelings were poetical, and tried to express them in words, but the words needed didn't exist and the ones he had weren't good enough. He wondered if other people had these feelings; he went searching for them in books and sometimes a writer or poet nearly captured something like he'd felt but there was always some little detail off, a bad choice of words, that invalidated the entire expression and left him crestfallen as if his own feelings had been wronged. Sometimes he'd be drinking with a guy or a demon or whatever, and they'd start down a trail of thought, trying to capture a feeling in words to share with him and at the end of twenty minutes or an hour he'd almost be there, almost understand--but it took all that struggle to tongue it. His own feelings were just as complex and difficult to trap.
Dru used to want him, but he was just one doll on a shelf for her. She wanted a tea-party, she wanted all the stars in the heaven, she wanted him to stroke her hair. He only realized now, when she'd been carved out of his life, how little he'd been with her even though he'd been with her all the time for more than a century. He'd been what she wanted, now and then, but she felt as much urgency of desire for him as she did for a new dress or dolly or dinner. Maybe no one, ever, had wanted him the way Xander did. He felt loved.
Idea that Wes's father dies and Wes goes to settle his affairs and opens his safe and finds all sorts of top-secret watcher documents, files, et cetera that would have been otherwise lost when the council headquarters blew up. He finds all these studies and position papers and stuff on vampires (and slayers), indicating that the information they give slayers and low-level watchers is partial or false. They know that vampires are really just the people they were when they died, that the demonic force is purely an animating one. They know that as vampires age, some become more animalistic and others may actually become more peaceable and human, especially those in the Aurelian line. There are many older vampires who feed only from animals or willing humans, who live quietly, passing for human, blending; watchers and highly-placed vampires in fact have worked together at times.
Stemming from that, an AU where Wes, now independently wealthy, takes unsouled Spike under his wing, takes out his chip, and indulges his predator's need to kill and feed.
Wes rescues a damaged, amputated Spike and spends weeks caretaking him while he's stuck in a mud bath with magical, flesh-regenerative slugs from another dimension. And when he's all better they make mad, passionate love and live happily ever after.