The study also found that people induced anger in themselves only if there was an actual benefit at stake for them in the negotiation. This qualification was essential in demonstrating that it was the perceived strategic benefit of being angry (and not, say, just a reflex that we have when entering any confrontation) that prompted people to induce such an unpleasant mood in themselves.

Whether induced or not, anger must ultimately be genuine in order to be useful in provoking concessions. According to a 2013 paper in the Journal of Experimental Social Psychology, faking anger, compared with playing it cool, leads a negotiation partner to see you as less trustworthy, and actually increases his demands on you.

There are other important caveats. While expressions of anger can elicit compromises, they can also lead to covert retaliation, according to a 2012 paper in Organizational Behavior and Human Decision Processes. In two experiments, negotiators overtly made concessions when opponents expressed anger but, evidently feeling mistreated, covertly sabotaged their opponents afterward. Outside the laboratory, this dynamic might take the form of acquiescing to an angry colleague’s demand but then spreading negative gossip about him around the office.

Anger also works better in negotiations when it’s directed at an offer rather than at the person making the offer, according to a 2011 article in the Journal of Experimental Social Psychology. Many of the same researchers also reported, in a 2012 paper in Personality and Social Psychology Bulletin, that expressing anger when you’re in a position of low power merely irritates your opponent and leads to a backlash. If you have less power than your opponent, they found, showing disappointment is a better strategy than expressing anger, as it can induce feelings of guilt in your opponent.

Expressing anger can sometimes benefit all the parties involved, not just one of them, by clarifying boundaries, needs and concerns. Think of the loved one who doesn’t realize how strongly you feel about the relationship until you express feelings of frustration with it. In a 2009 article in Negotiation and Conflict Management Research, the authors found that anger is more likely to lead to such mutually positive outcomes when it is low in intensity; expressed verbally rather than physically; and takes place in an organization that considers it appropriate (like a labor union or a university athletic department).