Buffy the Vampire Slayer, episode 3.20

"For gods sake man, she's 18, and you have the emotional maturity of a blueberry scone. Just have at it would you and stop fluttering about."

It's prom. It's an emotional story and people say nice things they wouldn't usually (bar Giles, above).

It's also 1999. Buff graduates in 1999.