Rainboe: A briefing is a bit like holding a door open for someone, its not compulsory, it IS courteous but you dont always get a thankyou..... If there is something that has proved troublesome and requires DD'ing I would sooner have a chat with the crew than not but then in our human factors we have always been taught the best form of handover is written and verbal.
Likewise, you dont need a special relationship with your caterers but it may stop them gobbing in your sandwiches if you keep them on side!