Buffy the Vampire Slayer, Season 4

Spike:
[happily] Now that was fun!

Adam:
You were successful?

Spike:
[scoffs] Easier than I'd thought it'd be, too.

Adam:
You're sure?

Spike:
[scoffs] Feel it in my bones. I call it...the Yoko Factor. [off Adam's look] Don't tell me you've never heard of The Beatles?

Adam:
I have. [stands] I like Helter Skelter

Spike:
What a surprise. The point is, they were once a real powerful group. It's not a stretch to say they ruled the world. And when they broke up everyone blamed Yoko, but the fact is the group split itself apart, she just happened to be there. You know how it is with kids. They go off to college, they grow apart. Way of the world.