Complaining is as useful for people's minds as a whistle vent is for a teakettle. We use the phrase "let off steam" because frustration affects our behavior the way heat affects liquid in a container. As the level of negative emotion rises, we feel mounting pressure. We can handle this pressure in the same three ways we can handle steam:

Option 1: Explosion

Many people try to deal with the hot vapor of irritation by simply choking it back. This leads to behavioral explosions, as you can learn from anyone who's ever tried to be the perfect, unruffled mother, only to find herself locked in the bathroom punching towels and using language that would make pirates faint.

Or maybe that's just me.

So here's another example: The nursing staff at an inner-city hospital once told me that although treating drug addicts and gunshot victims was a scary proposition, the most terrifying thing they ever had to face (no offense—I'm just repeating what I was told) was a partially anesthetized nun. Dramatic things happened, the nurses averred, when a holy sister from the neighborhood convent was "going under," drugged just beyond inhibition but not yet to oblivion. The nurses told tales of physical violence, of naked escapes from the OR, of destructive rampages through other patients' rooms—all perpetrated by brave, godly women who in their right minds never vented about anything.

Apparently, even those of us with the awesome self-control of religious renunciants occasionally need to release psychological pressure. You wouldn't want to emerge from an appendectomy to discover that you've decked the entire surgical team with your own IV rack, would you? That's where a strategy of controlled release comes in.

Option 2: Venting

The effect of emotional venting is to sustain an unsatisfactory status quo. Most people think the opposite, that complaining is part of an effort to change an unsatisfying situation. Nope. Complaining lets off pressure so that we neither explode with frustration nor feel compelled to take the often risky steps of openly opposing a difficult person or situation. Keeping emotional pressure tolerably low doesn't change problematic circumstances but rather perpetuates them.

For instance, Regina is a Mexican-American whose white racist parents-in-law treated her abominably. She complained about this to her husband every day. When I asked why she talked to her husband, she said she was starting an information chain: She would force him to force his parents to change. How long had Regina been employing this strategy? Twenty years. And the effect to date? Nada.

Mike worked for a pompous boss who gave his subordinates little direction and less support. The underlings spent their work hours muttering angry stories and following the soap opera of office conflict. Mike came home exhausted, not from working but from venting. And things at work kept getting worse, not better.

College sophomore Dinah spent hours with her friends ranting about a certain high-ranking elected official, who shall remain nameless. This, Dinah told me, was activism. I said it looked more like passivism—neither activism nor pacifism but an excellent way of feeling intelligent and important without studying.