In season seven’s First Date, just after Wood successfully asks Buffy out, we see him take out a knife which is in a bloody handkerchief. He then rubs it clean and puts it in his Rack ‘o’ Blades. However the blood is dried in the handkerchief and on the knife …

In the episode Restless (time: 19:18) while Xander is going in the back of the van he passes a window. Just as the window vanishes to the left side, you can see the bluescreen instead of the moving lane.

At the end of the episode Same Time Same Place when Buffy and Willow are sitting on the bed and Buffy admits that she thought Willow might have been behind the killings that Gnarl did, she says the following line:

“I wanna be the kind of person that wouldn’t think that. …

In School Hard (2.03), when Buffy is in the alley at the Bronze fighting the vampire that Spike sent out to “get something to eat”, Buffy yells to Xander that a stake would be nice. Xander runs in the Bronze, grabs her bag, pulls out something I can’t make out …

In Never Leave Me, Spike tells Buffy, “You’ve never met the real me.” If he’s refering to his former evil-ways, wouldn’t she have “met” the real him in seasons 2-4?