It is all about control, excessive testosterone develops a greater need for control over your environment ie. you have a greater competitive attitude to all elements with in your environment, human and otherwise. Angry faces are there because you are creating them, forcing a change in the emotions of others around you and specifically forcing them to adopt negative unhealthy emotions and stealing away their ability to control their mental state ie. challenging them and winning.
...but isn't this classic Alpha behavior? Do the psychologists even study chimps and gorillas any more? If your underling (or a potential threat to your rule) only briefly shows an anger face but not long enough to be perceived as a threat, that means you 'won' the confrontation and have established your superiority in the heirarchy. Of course, with chimps it's actually the ones that stay on the fringes and avoid the Alpha (we'll call them Chimp Geeks) that have the most sex with the females, as the Alpha & underlings are too busy and stressed about staying on the top o' the heap...
Description: From a LA Times Festival of Books, a panel on domestic politics and U.S. foreign policy featuring: Amy Goodman ("Static"), Douglas Kmiec ("The History, Philosophy, and Structure of the American Constitution"), Greg Palast ("Armed Madhouse"), and Doug Wilson ("Getting America Right"). The discussion is moderated by Larry Mantle.
Description: From the LA Times Festival of Books, a panel on political spin featuring: Frank Luntz ("Words That Work"), Joe Conason ("It Can Happen Here"), David Goodman ("Static"), and Michael Isikoff ("Hubris"). The panel is moderated by John Powers.
Description: Book TV presents LIVE coverage of the LA Times Festival of Books. At 1:30pm ET/10:30am PT, a panel on the mixing of religion and culture featuring: Christopher Hitchens ("God Is Not Great"), Zachary Karabell ("Peace Be upon You: The Story of Muslim, Christian, and Jewish Coexistence"), and Jonathan Kirsch ("A History of the End of the World: How the Most Controversial Book in the Bible Changed the Course of Western Civilization"). The panel is moderated by Thane Rosenbaum.
Description: Book TV presents LIVE coverage of the LA Times Festival of Books. At 5:30pm ET/2:30pm PT, a panel on the Iraq War featuring: William Langewiesche ("The Atomic Bazaar: The Rise of the Nuclear Poor"), T. Christian Miller ("Blood Money: Wasted Billions, Lost Lives, and Corporate Greed in Iraq"), Robert Scheer ("Playing President: My Relationships with Nixon, Carter, Bush I, Reagan, and Clinton--and How They Did Not Prepare Me for George W. Bush" & "The Five Biggest Lies Bush Told Us About Iraq"). The panel is moderated by Nancy Snow.