I would like to take this opportunity to share my appreciation for a specific bit of the score in Ferris Bueller's Day Off.
When Charlie Sheen and Jeanie are saying good-bye, the score becomes a realistic doo-wop song that reacts to the script in real time. "My name is Jean, but...some guys call me Shauna."
"Shauna...Shauna...Shaaaaunaa Jeeeeaaaan..."
This level of self-awareness in a score is absolutely unheard of and one of my favorite moments in all movie music.