One trick to calming intense conversation at work, or at home, is to wait 10 seconds before responding to what the other person says. Over at Inc., Jason Aten explains that it works because it instantly "freezes the crazy cycle… what happens when we are offended or frustrated and respond negatively in an effort to get another person to change." It also requires the other person to chill out for a moment and, lastly, he says, it "gives you a chance to refocus on the people you're communicating with, not just the topic."
While all those things are likely true, I think the pause also helps with perception. By hesitating before you respond, it appears that you're at least considering what the other person has said (even if you have already decided they are full of shit).
"How the 10-Second Rule Can Dramatically Change Your Conversations and Make You a Better Leader" (Inc via Digg)