Language is like a chameleon: it changes its colors according to the place where it is. What can be considered as good use is using language with certain standards in mind. Such standards do not necessarily have to do with grammatical correction; it is actually a matter of social context. Depending on where one is and whom one talks to, language will certainly have to be used differently, that is, in a particular, sometimes even peculiar way, if one's goal is to get himself or herself across.
A certain level of grammatical correction is necessary, sometimes more, sometimes less, but it has to be there. After all, certain elementary rules must be followed so communication can be achieved. There are language conventions that cannot be taken for granted if one wants to be understood.
A certain quality of language and usage must be maintained. That does not mean one has to talk like a scholar who is giving a lecture all the time. One should simply bear in mind the various situations of communication, the many different contexts in which individuals from all walks of life interact and talk. The rules of context correctness can be applied by always using common sense. Language effectiveness requires sensibility and empathy. Depending on the context, this or that approach must be used.
