Quotes never heard of before? Well, I've used a script a long time ago and I have the EVERY single speech file for each character. From unused mission dialog to conversation dialog. I've also got mission music, cutscene dialog and ambient sounds as well.
If you want to hear some of this "unused dialog" for some of the characters, skip to 9:14 in my
Preppies VS Greasers : The final showdown video. Theres lots of other places where I've put the unused dialog to good use, but this is just a little example.
It's a pity rockstar did not use all of the extra dialog for some of the missions. In the end rockstar only used up roughly 40% of it all.