I realized how useless anger generally is after I acted angry at my young kids a couple of times. All it did was amplify my frustrations and show them an unhealthy behavior they would imitate when they were frustrated.
This "mirror" that my kids held up made me realize how stupid I was, when I was thinking that I could yell at them to get them to do what I want.
I used to defend occasional anger as a natural force that can help to change things for the better. I used to think that without anger there would never have been any revolutions, the oppressed would never have thrown off the oppressors.
But now I am not so sure anymore. Maybe the "angry mob" was mostly just used by others during revolutions and only cool-minded, well planned uprisings actually changed society in a progressive way.
Also, I used to be a defender of very honest (some would say harsh) criticism and a sometimes very confrontational style of debate. Sometimes I would get really mad when small things seemed really unfair, inappropriate etc and I felt like justice was or should be on my side. Those situations then either backfired and/or added to my reputation as a loud mouth.
Now I am at a point in my life where I am reassessing my cognitive and behavioral patterns and want to be more balanced, more efficient and have less friction happening, at work, at home, within my family and in public.
This goes along with less problem-oriented (more solution-oriented) thinking, less big picture complaining and more pragmatic doing, less dwelling on frustration and more goal-oriented planning.
I can still get frustrated when I see how the majority often seems passive and indifferent, and I am often more likely to speak up or act on something that bugs me than others do. Sometimes that can also be perceived as a (mild) form of trouble-making but I like it better than swimming with the flow all the time.