Five signs that what's bothering you might be only the start of the problem.
Anger is a feeling you may think you can spot a mile off. When someone cuts you off in traffic, or your child intentionally drops your cell phone in the pool, or a supervisor shouts at you, even the most mild-mannered among us feel their temperature rise. Depending on your disposition, you either sigh and move on, make a sharp remark, or if you're really ticked off, veer into Fight Club territory.

It's only natural, say the Seattle-based husband-and-wife team David Barash and Judith Eve Lipton (he's an evolutionary biologist and professor of psychology; she's a psychiatrist). As they explain in their book Payback: Why We Retaliate, Redirect Aggression, and Take Revenge, anger is hard-wired in human beings and in all creatures, from chimpanzees to cats, even to birds and fish—and so is letting it out. In lab tests, animals that lash out at others when they're under stress are healthier than animals that don't.

But aggression can take a variety of forms—and some of them are not as easy to detect as enraged lab rat no. 9. Barash and Lipton, and another expert, Neill Gibson, who with Shari Klein co-authored the manual What's Making You Angry, reveal some of the disguises of this powerful emotion.

"Almost every depression has anger in it," Lipton says. "They go together like peanut butter and jelly." Freud famously called depression anger turned in on the self. The biggest sign that a depressed person may have anger issues is self-destructive behavior. Take the acting teacher in the Northwest that one of our experts knows: He's been out of work for a year and a half but has quit applying for jobs. Instead, he applies for new credit cards and charges new clothes and expensive therapy sessions—which aren't getting him closer to what he wants. Self-defeating choices suggest that you're not able to express what's upsetting you.

Not-So-Comic Relief
You might know this woman. You might even be this woman—the person who thinks she's in a great mood, despite a god-awful week at work and a terrible date the night before. At a party, dressed up and a little keyed up, she jokes with friends about her cold-fish boss and the ridiculous cheapskate she'd been set up with. There's nothing wrong with making light of life's subpar moments—that's what people do, don't they? Not exactly, says Lipton, "Telling jokes that make others look bad is a form of retaliation." It's a way of venting annoyance that you can't say directly to the person.

Extreme Helpfulness
Some of the subtlest forms of anger come in the form of excessive kindness, says Lipton (which makes us think of Dexter, TV's good-guy serial murderer, who takes glazed donuts to the office as cover for his secret life). But Lipton is speaking of more commonplace interactions: She gives the example of the mother-in-law who brings a show-offy, gorgeous dessert to a family dinner unasked—feigning assistance—but who really wants to show her unappreciative daughter-in-law that she should be more highly respected. 

Ongoing Nit-Picking
A similar tactic is used by people who continually correct others—like the husband who helpfully reloads the dishwasher to show his wife that she has done it the "wrong" way, or the wife who criticizes her partner when he does the laundry differently than she does. This kind of behavior hides hostility under the guise of instruction, says Lipton. It's a power play, and a form of redirected aggression—what you're saying is not, Let me show you how it's done, but instead, Let me show you how it's done, you idiot.

The Wrong-Person Romance
"There are three major triggers that get people and other animals revved up," Lipton says: "Lust, fear and anger all make the heart beat faster, the stomach digest slower and blood pressure go up. They're all connected. And sexual behavior that upsets your partner is likely an expression of anger." Gibson explains, "The instant someone tells themselves, 'My partner should be more sensitive to my needs,' or 'My partner should be better looking,' then you're talking about anger: the anger of should thinking."

"The bottom line here is that anger causes pain," Barash says. As long as we're trying to treat the pain, the root cause—whatever it is that's annoyed or infuriated you—will remain. "It's too bad we don't have barometers on our chests that tell us when we're angry," Gibson says. But by determining if anger is the actual culprit, you can start to get some relief. As a first step, the experts all recommend talking about what's made you mad...with the person who made you mad. Which makes perfect sense—in a perfect world. For the rest of us, the three experts suggest that when it's just not possible to confront the person or change the upsetting situation, exercise is a no-fail anger outlet, as is meditation. Humans may not be the only creatures that get angry, but we're the only ones who can ease its effect by identifying it, analyzing it and dealing with it.

Start Moving On from Your Anger