This was very perceptive. I don't think I understand the concept of being a "polite" person, though. People think that pretending to be cordial will make them popular?
I once saw a debate about the nature of politeness where they used the phrase "politeness is not the appearance of respect, it is respect for appearances". There's probably a lot to that. In a certain way, filtering what you say and do is respectful towards the people around you and shows respect for the social arrangements of the society you live in and form a part of. It is not about faking cordiality, it is about creating a liveable environment for everyone.
I my personal experience people who are very proud of always speaking their mind tend to be extremely self-centered. To always bluntly speak your mind and put your self-expression before the wellbeing of others is often egotistical, selfish, inconsiderate and cruel.
The good life is one inspired by love and guided by knowledge. Neither love without knowledge, nor knowledge without love can produce a good life. - Bertrand Russell A herring's blog Johari / Nohari