I also have this blunt,honest and some people may call,rude,polish trait.
I would not call being upfront , honest and speaking one's mind a Polish trait as such. You have described me to the letter and I am English. I don't perceive it as rudeness, and while I would not go out of my way to be deliberately unkind or offensive, I would rather deal with people who speak their mind than those who don't. What would be the point of asking for an opinion, only to be lied to? That is being dishonest. If some people want to interpret that as being rude, then that is their problem.
Having said that, the majority of Poles that I know have a very similar mindset to my own.
I hate that fake American politeness..
Me too. Unfortunately the sh1t eating grin syndrome has made its way across the pond :-(