There is within me a great, raging conflict, an unstoppable force meeting an immovable object, that keeps me awake at nights—neurological fuck-ups notwithstanding—and it concerns the matter of writing.
As a sociolinguist, albeit of the dismal, failed variety, I know that there is no such thing as “correct” or “incorrect” language use; that we acquire our habits of speech from our social environment; and that to assert that certain forms are truer, more accurate, or better is to impose a distasteful and discriminatory social elistism that sets the particular patterns and habits of the privileged few as an unjustifiable standard, and then uses them as a stick with which to beat people who never had exposure to these norms and cannot therefore be reasonably expected to reproduce them.
As an editor, however, I know that there is a right way to do things, and that you just did it wrong.1
The sociolinguist wins, almost all the time, but there is an interesting issue around punctuation where the waters are a bit murkier. Speech is, of course, punctuated; but the mechanisms of punctuation are very different to those of writing: pauses, gestures, facial expressions, and non-verbal cues such as (in English) tone and intensity. Written punctuation is a very different matter: it belongs entirely to the realm of literacy, and literacy is a secondary skill that supervenes upon language use and is learnt rather than acquired.
We learn a great many skills as children, some formally (such as arithmetic), other less so (such as wedgie technique). In the context of formal learning, it does not seem as egregiously unjust to propose certain favoured norms, as it is no longer the case that the naturally-acquired habits of a few are being imposed upon and in contradistinction to the habits of the majority. We all must learn the norms of literacy and, as long as the proposed norms do not surreptitiously support or reinforce the spoken behaviours of the elite, then I cannot find it in myself to object too strongly.
Punctuation, then, seems a clear position where the editor in me can flex his muscles a little. Spelling, less so: we may have standardized spellings, but these could be seen to be imposing certain pronunciations over others. But punctuation is so arbitrary and independent of lexical content that here, at least, I feel I may be entitled to allow myself a little prescriptivism.
Does this mean, then, that I decry the grocer’s apostrophe—as more than a few people think I should?
Well yes, and then again, no. I cannot deny that I wince when I see it but—cursed egalitarian that I am—I rather feel that in this class-bedevilled society certain groups of people have access to higher-quality education than others, and that members of that group with access to only the poorest level of schooling are more likely to go on to be grocers than, for instance, Old Etonians. I don’t like to see the grocer’s apostrophe, but I find it very hard to lay the blame at the door of the individual who has written the sign.2 The putatively terrifying deficit aside, we are one of the richest nations on the world and, if we are to promote cross-dialectical norms in even this one small matter, it seems a piteous failure of our society if we cannot manage to educate everyone about it.
 In fact, of course, “you just did it wrongly.” Case in point, however: both forms are equally understandable, and the insistence on the “correct” use of the adverbial form just results in a cumbersome and ugly locution, not to mention ruining some of the effect by terminating an humourously over-emphasized phrase on an unstressed syllable.