"Squelch my reaction. Not expressing anger often allows it to dissipate." Wait. What? This is the worst piece of amateur un-advice I've ever heard. Pretty much every trustworthy source on anger management or mood psychology in general agrees that suppressing feelings of anger is about as physiologically unhealthy as expressing anger inappropriately or excessively. Both approaches are equally likely to contribute to high blood pressure, heart disease, and early death. Plus, habitually suppressing anger will turn you into a passive-aggressive little shit, and I HATE those backbiting little turds and their whiny manipulative....

Sorry. Got sidetracked there.

Supressing anger does -not- allow it to dissipate. What dissipates with the passage of time is the physiological -experience- of anger- the flood of hormones and neurohumours that are generally flushed by the CNS after about 40 seconds assuming you don't do anything to keep up production. Suppressing natural responses is immensely effortful, and contributes to all those heart-related problems I mentioned above.

So, honestly, I think this is really unambiguously bad advice. It sounds like in the author's case she's doing it to head off inappropriate or excessive expressions of anger that would cause more problems than silence, but frankly, she (and anyone) would be a lot better off finding a sublimated or moderated form of expression rather than 'squelching' anything.

Your post made me curious so I looked for any references to studies or anything on the Happiness Project website. I found a post where Ms. Rubin sad the following:

As I say in my post, check out Haidt's Happiness Hypothesis.

Also look here, for something online: <link>

The study referenced doesn't exactly support her point, but more takes it as a given and references studies that do support it. In definitely seems to indicate that your belief that squelching anger is unhealthy is a myth. This is the concluding passage:

Our findings suggest that media messages advocating catharsis
may be worse than useless. They encourage people to vent their
anger through aggressive action, and perhaps they even foster the
displacement of aggression toward new, innocent third parties. In
our research, people who received procatharsis messages first
chose to vent their anger by hitting a punching bag, but then they
went on to show elevated aggression toward the person at whom
they were angry. They even showed increased aggression toward
an innocent third person. Pop writers may think they are offering
helpful, sage advice on affect regulation, but the effect of advocating
catharsis may be to cause a general increase in aggressive
behavior. Perhaps media endorsement of cathartic release should
come to be regarded as a potential danger to public health, peace,
and social harmony.

Like I said, this particular study doesn't prove anything, but it references other studies you can look at if you want evidence of what Ms. Rubin claims.

There's a couple of problems with this argument, though I greatly respect your willingness to cite peer-reviewed research on its behalf. I have two such problems, the second propagated by the first. The first is that I'm not talking about catharsis. (I was quite careful not to use the word in my discussion of the healthier alternative.) Catharsis, in itself regarding the individual's well-being, isn't especially productive as regards moderating anger (though in the long run, it isn't extremely counter-productive, either). I've certainly seen examples of anger management where individuals are taught to redirect expressions of anger, such as breaking a pencil or stomping your foot instead of, say, punching your therapist, which arguably has some practical benefits. :) My second assertion is that your response, "it definitely seems to indicate that your belief that squelching anger is unhealthy is a myth" is incorrectly inductive. Simply because catharsis is not itself therapeutic, it does not make its supposed 'opposite' approach, squelching anger, itself beneficial. There are many other anger management techniques that fall between and outside of catharsis and so-called squelching.