Hi there Thomas,
"As you talk, you pay too much attention to what you are saying, looking for errors or things that you could have said better. And when you hear the mispronunciation of a word, the wrong use of a word, etc., you agonize over it
." That`s me Thomas.
I couldn`t agree more with every single line you wrote, except for when you deduced my English might flow at its best when I`m nervous or sad (quite the contrary, it simply vanishes lol).
Anyway...I understand it when you mention that we usually give so much importance to having a minimal accent. Unfortunately, at first, having/or not having a "heavy" accent might bear on the way you "fit in" a particular society (for example, some people might think you don`t know the language enough because of your accent and tend to "dumb down" the level of the conversation ).
Mind you, only a good/advanced/proficient user of the language in its main fields (speaking, writing, listening) will be able to have real credit when dealing with native speakers (at least in the long run).
If you have a look at both videos below, you`ll notice that besides having a "heavier" accent when he talks (conspicuously "marked" by the rythm of the Portuguese language), Celso Amorim`s English (he is the Minister of External Relations of Brazil) run circles around the English spoken by Brazilian Victoria`s secret angel Isabeli Fontana. Her English is bubbly, her accent mild but it is clear how she lacks vocabulary.
Anyway, the point is that once we are living in a foreign country, there is a kind of feeling that makes us want to "fit in" a little more (I`ve just moved out of Brazil, therefore the attempt to adjust the "tone of my speech"). I`ve read some articles about it on the internet by a famous linguist called "Ron Martinez". Martinez argues that the wish to blend in to some extent in a particular society, when brought together with dedication to study, effort etc leads the non-native speaker to reach a level called "ultimate attainment". As I am not a linguist myself, the only aspect of this concept I could highlight would be that the ultimate attainment represents the ability to pass as a native or proficient speaker in some situations
People who reach the ultimate attainment are called "passers". Passers are almost never able to pass 100% of the time, but in some occasions what they say comes out just "perfect". You know those situations in which someone pays compliments to your English or even mention they thought you had been living in that place for quite a while. Without a doubt, it shoots up the non-native speaker confidence and "self-steem". That`s enough for the passers, because they know they`ll never sound like the natives.
The mathematics of the ultimate attainment would consist of something on the lines of:
A: PREPAREDNESS FOR SITUATION + B: FAMILIARITY WITH WORDS/EXPRESSIONS IN THAT SITUATION + C: STRONG DESIRE TO NOT HAVE AN ACCENT = LIKELIHOOD OF ULTIMATE ATTAINMENT As long as the non-native speaker in question does not bother, there is no need to become a "passer".
However, I`m of the opinion that when the non-native speaker proficiency comprises great pronunciation skills, that`s a winning combination. Amazing opportunity to discuss this