When I'm working with a band that I'm unfamiliar with I always start out acting quiet and polite, but by the end of an album (sometimes as soon as the end of the day) my cynical/smart-ass side starts to get comfortable and I start talking too much. Most of the time I run the same joke into the ground, or pick on one of the band members in a joking manner, but as exhaustion sets in I find my mouth opening before I can think and sometimes the wrong thing is said at the wrong time. In order for others to achieve proper studio etiquette, here's a list of things that should never be uttered while you're in session with your wonderful clients.
1. Umm, that was interesting, I guess. (after any overdub or take)
2. Have you heard this song before? (ditto)
3. Has anyone introduced the drummer to the bass player? (after a sloppy take)
4. How long have you been playing together? (after a really sloppy take)