'I have a friend who is Polish, she is very smart, but she has a very thick accent'
My cleaning lady is Polish with a very thick accent as she comes from near the Russian border. This is compounded by the fact we have to communicate in French, which she speaks very fast and I speak slowly. Frequently, I have to ask her to speak very slowly so that I can understand what it is she is saying/asking. So, I don't always understand her, but that doesn't make me ignorant, just slow at deciphering rapid fire French delivered with a thick accent.
We frequently go out to dinner with non-native English speakers as dh works in a large multinational organisation, and it is difficult to decipher what they are saying at times, not just with accents, but with syntax as well.
I am also on the receiving end of this as my Flemish is appalling, and I get blank looks and then spoken to in English, so the problem of not understanding my Flemish accent/syntax/verbs/vocab is avoided. It's not ignorant not to understand, it can be hard.