I've found that my hands down favorite parts of both discs are the commetary. There's something surreal and really hilarious about listening to Kevin Smith and various other people talk about the movie.
In JaSBSB, there's a scene featuring Marc Blucas, who you may know as Riley on Buffy, and who I know as the human incarnation of pure evil. During the commentary, it gave my great joy to hear Kevin Smith and Scott Mosier both sit there going, "Who's that guy from Buffy? Don't you remember his name? What was his name? Oh man, I can't remember. Can you remember? Does anybody remember? You watch Buffy, don't you? Do you remember?" and then Jason Mewes goes, "I know his name on Buffy was Ryan..."
I. LAUGHED. SO. HARD.
No less than half an hour later, when nothing even remotely related to that scene was going on, Scott Mosier goes, "I remembered that one guy's name. It was Marc Blucas."