Xander Harris wasn't someone Spike really cared about, even with a soul. He tolerated the whelp because the boy was one of Buffy's closest friends, yet personally the bleach blonde vamp would've been perfectly content to never see Xander again. It wasn't the fact that Harris had nearly beaten Spike to death when he was still chipped. Nor the way he had constantly put Anya down either whenever the girl was earnestly questioning things either. Not even all the constant snide little barbed remarks, or the constant way that the human had belittled the vamp at every possible turn. Hell even the way the whelp had always been so bloody hypocritical and judgemental could have been forgiven too.
No...the thing that ensured a rift between Spike and Xander lingered even now was the way the boy always seemed to be so sodding entitled when it came to trying to tell Buffy how she should live her life. As if he had any bloody right. But still Spike had seen it played out again and again; those endless guilt trips and all the whining. Of all the Scoobies, Tara had been his favorite. Even Red and Anya were folks Spike cared for too. But Harris...Harris was someone Spike was fine with never seeing again. So just hearing Buffy remark that the boy had had the worst of it caused a slight frown to tug at the corner of the vamp's lips for a second. Sure his view of things had been a bit skewed back then; but William would've reckoned that having been kidnapped, tortured, the victim of experimentation (and brain surgery) at the hands of a shadowy government division, left to starve to death, rendered completely harmless (effectively neutered) and then bound and tied up by the very ones he had gone to for help...only to be mocked, ridiculed, and shot full of arrows...he figured that might have possibly rated a little higher on the 'worst' scale then a bit of magical syphilis that cleared up.
Oh he understood how things were back then. Understood that going from a blood thirsty nemesis, to an ally who stood with em all against the forces of Evil, was quite a lot to process. Spike knew that he had caused em all pain, and that gave the Scoobies plenty of reason to doubt his motives too. Still over the last few years nothing had ever changed. It didn't matter to em that he had spent nearly five straight months looking after Dawn; patrolling with em all, and helping to keep them all safe when Buffy had passed away. No, the moment Buffy returned (after having literally been ripped from Heaven's embrace by her friends) the Scoobies went right back to playing kick the Spike. All while ignorantly failing to see just how much pain Buffy was in...and instead of being there for her those wankers just expected her to be bloody grateful and go back to Slaying with a smile. Just thinking about it all had him growing lost in a spiral of dark thoughts.