This is an interesting view that I can wholly agree with.
Without manners, it's easy to enrage some more belligerent characters, and progress is not made by the enraged. Rage can fuel determination, but not a determination for good. That's a bit of a tangent, there, but manners can get you far in life (here comes a tangent anecdote). People sometimes comment that I am "too polite," sometimes with less tasteful words between "too" and "polite," but I have never been in a fight in my life, even though there are some people I've known that could drive me to doing so. I'm confident that by clinging to good manners, I've helped calm and even amuse others, while at the same time opening doors for myself.
Note that attacking a horse-drawn carriage is not good manners.