I have a fine command of my native language and no guilt or shame at all about it at all....and I find it amusing that you think I should.
There is no problem with the active side of your English. The glitch is with your attempts to read between the lines. You assume things are said when they aren't, and then you do what you accuse Poles of doing - you become arrogant, take easy offense when obvious flaws in your post are pointed out, you apply blanket statements and you don't admit mistakes. You may have heard the term "projection" as understood by psychologists. Try to control it.
You have some experience with Polish speakers and teachers of English, I supplemented that with mine, which is contrary to yours. In fact I was an ESL teacher in New York City myself and my employer did not see any problems with the fact that English is my second or third language. About the only issue was my, then, RP accent. The school's management wasn't particularly thrilled about it. They like NYC drool much better. It took me about a year to fix that.
American professors from renowned schools offer highest praises to Polish universities where English language and literature are studied. But you know that this is not possible, huh?
Oh, and let me assure you - if I wanted to offend you I would leave no doubt in anybody's mind that this is exactly what I am doing. For now I don't even have to do it. I would suggest that what you wrote here is more offensive to yourself than anything you think you found between the lines of my posts.
I don't believe in any miraculous methods. They are mostly gimmicks. The method that always works is a lot of time, mind and practice put into the learning of a foreign language.
I was commenting Darius flamboyant style of writing.
I feel honored.