Epileptic Trees: Ford exhibiting some brass balls and asking about his "reward", to Spike and Dru blankly stare back. There's some debate as to who did the actual siring, but from the way she slowly opened her eyes in response to Ford's question, and the fact that she hadn't gotten a "treat" yet, Drusilla's a good bet.
Harsher in Hindsight: The ending of the episode is an in-universe example. Depressing and sad when aired, but the characters hadn't suffered great tragedy or major deaths yet. By the time the show is over that ending is second only to "The Body" in tear factor.
Moral Event Horizon: If Ford wasn't over it just by helping to mastermind the whole vampire pact, he's definitely over it when he knocks Buffy down the stairs while she tries to reason with the other clubgoers. Of course, as Buffy points out, he wanted to be the villain - it just made the whole death wish easier for him.