Not everyone has a mind that works like yours.
I start speaking in a slight version of the accents I hear around me, and I do this subconsciously, and then I realize I am doing it and I worry that I offended someone.
Like around Mexicans (the most common occurrence here in Dallas), I start to talk the way Mexicans around me speak English. My girlfriend told me about it one time, and she said it was kind of obnoxious. I do not do this on purpose (but maybe I should).