I don't spin, but that drives me crazy in boot camp, too. You're lowering the intensity of the whole group if your conversation is more important than the next thing the instructor is about to tell us to do. If he has to wait between activities for you to finish your sentence, then my heart rate is going down during that break and I don't want that! (Of course, if the instructor would be a little less polite, I'd like that, too!)

Karen