I've been watching several Roz clips on youtube lately. What a great character! Her very last scene, when she had Boo's door shredded, was especially thought-provoking to me. I think she realized that Sulley had formed a strong bond w/Boo and she was genuinely sorry to shred Boo's door, but she realized that if Sulley continued to see Boo, he would lose his ability to scare effectively, and there would be no more power for Monstropolis.

I sometimes wonder if Roz herself made contact w/a human child at some point in her life. Maybe that's why she worked so hard to uncover the scandal at Monsters Inc. She seemed to realize that Boo wasn't dangerous and she seemed to care about her welfare. Anyway, a movie about Roz's story might make a very interesting prequel.