Our "Anglo" nations are mostly monolingual, but take it for granted that everyone else should speak English. As a result we sometimes forget how much effort was put into learning it, probably partly because we ourselves never achieved the equivalent.

It could be that your English is so good, that individual mistakes (here I'm going to be guilty of using an idiom) stick out like a sore thumb! You were probably right to be proud

This is absolutely right. It would be cruel and unusual to pick on some particular word when someone is clearly a beginner in English, but when they are otherwise very good and they make an incongruous mistake it grates. I think people feel better about correcting or good-naturedly making fun of errors like this because it's implied that "your English is so good it's funny that you got that one small thing toally wrong". Of course this is often not so well appreciated by the recipient for various reasons.

> stick out like a sore thumb

I am going to memorize this one.

I've been guilty of doing this to my German friends, as well, but it's because I consider their English almost native level. It's the same to me as pointing out to a Texan that I find their pronunciation funny. In a strange way it's a compliment to them, but after reading your post I will remember to be more thoughtful about how things like that could be perceived.

As an American in Germany trying to speak German, I've made some effort to hide my accent. But then I think about Arnold and Werner Herzog. Would they be who they are without their accents in English? Then again, no one here has ever mocked the way I speak.

Many of us associate the accent exclusively with Arnold. LOL. Don't take it too personally. We like Arnolds accent and to us it sounds like all Germans are impersonating Arnold.

The problem I saw and still see is that it disqualified me from the whole discussion, despite having something 'valuable' to say. But you are right, I don't take it personally (anymore) and actually can think back about this with a smile ony face.

Similarly... at first it sounds like all Icelanders speaking English are impersonating Björk. But it's just the Icelandic accent.