> If there's any tension or negativity between you and a client, just speak softly. It will instinctively make them feel over-dramatic and they will gear down.
I've heard in some cases doing this in the face of red hot fury can make things worse and you shouldn't be afraid to suspend the meeting and reconvene after a short break. Of course that needs a manager with enough of a backbone not to throw their team under the bus by sitting back and letting the client tear shreds off them.