The Buffy and Angel Trivia Guide // No warning

In Triangle, Anya told Xander that if he ever decided to leave her she wanted a warning (such as a big bomb-clock) and some way of preventing it (such as cutting the right wire). When he did leave her, in Hell’s Bells, he had obviously forgotten this conversation. Anya got no warning, and had no way of preventing Xander from leaving, which was exactly what she’d feared.