For me, anger can be a super useful emotion.
In everyday life, I usually have a problem saying "no"; not just to people, but also to ideas and things. I am trying to keep all doors open, and I am keeping stuff just because with some tiny probability it could be useful in the future.
When I get angry, burning bridges or throwing away stuff becomes much easier.
The key is to have the emotion under control (as opposed to being controlled by the emotion). Having emotion under control is not the same as not having the emotion; it means being able to calmly consider things regardless of the emotion, and then letting the emotion burn only in the places you decided to let it.
For example, I can decide which parts of my life need to be changed, and then let my anger attack those parts specifically. (As opposed to letting the anger itself decide which parts of my life it attacks.) As a strawman example, I could decide to only eat broccoli and to avoid chocolate. Then I would wait until something naturally pisses me off (I am good at redirecting the emotion, not at creating it ex nihilo), and then I would irrationally spin the anger against the chocolate: "Fuck this chocolate! It is ruining my whole life! I swear I will never touch this shit again!" Heh.
Alternatively, just watch the film Inside Out. I found it amusing how at the start all the emotions seemed to have a purpose, except for sadness, which was told to just, "Keep all the sadness in this circle".
I guess the distinction I would make here is that negative states aren't intrinisically good, but they may be instrumentally good for all the reasons given above.
The Upside of Your Dark Side: Why Being Your Whole Self–Not Just Your “Good” Self–Drives Success and Fulfillment. By Todd Kashdan & Robert Biswas-Diener. Avery, 2014.
This book was written by a pair of psychologists who thought that the excessive focus on good and positive feelings in positive psychology was a little overblown, and that the value of so-called “negative” feelings or aspects of personality was being neglected. They do think that it’s good for us to be happy most of the time, but that it will be even better for us if we have a flexibility that allows us to switch to non-happy states of mind when it’s beneficial. They suggest an 80:20 ratio as a rough rule of thumb: be happy 80% of the time and non-happy 20% of the time. They call this philosophy “wholeness”: a person is whole if they are able to flexibly tap into all aspects of their being when it’s warranted.
The authors offer a number of examples about the value of so-called negative states. Too much comfort makes us oversensitive to inevitable discomfort. Anger motivates us to act, fix injustices, and defend ourselves and our loved ones; guilt tells us when we’ve screwed up and motivates us to improve our behavior; anxiety helps us catch mistakes and take safeguards against risks. Happy people are less persuasive, can be too trusting, and are lazier thinkers. Intentionally trying to become happy easily backfires and makes us less happy; and there are situations where happiness feels inappropriate and will make others respond worse to you. Sometimes it’s better to act on instinct or engage in mind-wandering than to always be mindful and think things through consciously. The “dark triad” traits of narcissism, Machiavellianism, and psychopathy are all useful in moderation and provide benefits such as fearlessness and self-assuredness.
The following paragraph from the final chapter is a pretty good summary of the book’s message:
The basic idea is that psychological states are instrumental. That is, they are useful for a specific purpose, such as finding your car keys, being physically safe in a parking garage, negotiating a business deal, or arguing with your child’s teacher. Rather than viewing your thoughts and feelings as reactions to external events, we argue that you ought to view these states as tools to be used as circumstances warrant. Simply put, quit labeling your inner states as good or bad or positive or negative, and start thinking of them as useful or not useful for any given situation.
While I liked the book’s message and agreed with many of its points, I felt like it was mostly trying to tell a story that sounds plausible to a layman, rather than making a particularly rigorous argument. The authors tend to base their claims on isolated studies with no mention of their replication status; some of their example studies draw on paradigms and methods that have been seriously challenged (social priming and implicit association tests); occasionally they made claims that I thought contradicted things I knew from elsewhere; and some of the cited empirical results seem to have alternative interpretations that are more natural than the ones offered in the book. It’s plausible that they are drawing on much more rigorous academic work and that the argument has been dumbed down for a popular audience: even granting them the benefit of doubt, the book still feels way too much like a collection of examples that have been cherry-picked to make the wanted points.
Regardless, the book’s general message feels almost certainly correct – after all, why would we have evolved negative states if they weren’t sometimes useful? – so if anyone feels like they’ve been overwhelmed with too many messages of positivity, I would recommend this book for inspiration and an alternative viewpoint, if not for any of its specific details.