Pre or Post Crack?

I was singing along with my ipod to an old Whitney Houston song...

Cubemate: Is that Saving All My Love for you? I used to love that song.

Me: Yeah, I love all the pre-crack Whitney songs... (while
frantically tapping away on the keyboard)

Cubemate: Wait? What? Pre-Crack! (starts laughing hysterically,
almost to the point of rolling on the floor)

Me: What's so funny? Whitney was great pre-crack... but post-crack?
I don't think I even know any of her songs post-crack.

Cubemate: (now rolling on the floor laughing, discarded staples and
paperclips in her hair)

Me: No really, what's so funny?

A whole conversation between myself, cubemate and a director followed.
We googled Whitney's discography to determine the "crack-line" (ie,
Bobby Brown) and the viability of her music pre- and post-crack.

But, I still haven't figured out what was so funny. Oh well...