A funny story about how good pronunciation may be bad for you.
I was on vacation in Spain (Malaga) two years ago. I'm a passionate cyclist - a 'roadie', that is I ride a road bike - or a racing bike - the one with funny curved handlbars. So, on one fine day I take my bike, leave the town and head north, to the mountains. After a while I notice to my horror that I'm on a motorway: the road where bikes are prohibited ('bicicleta prohibita'). I think to myself 'I'll take the next exit back to the town'. And immediately a police car overtakes me with a siren and pulls over in front of me. Two big Spanish policemen come out of the car and walk straight to me. A couple of words on my Spanish though: I can barely say anything in Spanish apart from a couple of simple everyday phrases. But I'm kind of a pronunciation buff: I can quite easlily pick up and imitate accents (not ideally of course but it just come naturally to me). So I greet them in my best Spanish ('Buenos días '). They start talking something rapidly in Spanish. I reply something like: 'No hablo Espanol, solo dos o tres palabras ((I don't speak Spanish, just a two or three words). The bigger policeman looks suspiciously at me, shakes his head and says, counting on fingers,: 'no', 'hablo', 'Espanol', 'solo', 'dos', 'palabras' - seis palabras! ('six words!') . The end of our conversation was in English (yes, Spanish policemen CAN speak English!) The outcome was that they put a fine of 50 EUR on me and escorted me back to the town. I'm afraid that they didn't believe me that I didn't speak Spanish and tried to fool them! So, never speak with a better pronunciation that is actually your general command of a language!