Converging accents

After returning to bz somehow one of the first things you recognize are the accents of the others - seems like they've got even more characteristic then they were, so that it takes more efforts to get the sense. Or maybe it's just the matter of adjusting (to English in general?) and in a week I won't notice any difference. In either case I guess that you use the English in the environment where it's nobody's mother tongue your accent might improve till it converges to some "best possible". But the same time it might evolve in the wrong direction if you feel too comfortable with the way it's easier for you to talk (not the way that should be correct by the standard) and you don't see any obstacles in conveying your ideas while deliberately worsening your accent.