I often see people complaining that the 'grammar nazis' (that's me and my friends, by the way) are too picky, and that one should be able to write as much like an illiterate moron as one likes, as long as it is not for publication as one's work.
Now on the face of it, they do have a point. You do not expect crystal finger bowls at MacDonalds (face it, you don't even expect real food), and of course one needn't take the degree of care in a casual conversation that just happens to be in written form as one does in one's Great Australian Novel.
However. Yes, you knew there would be a 'however', didn't you. Because it's me. Or rather, it is I. Let's continue the food analogy for a little while. It's quite a good analogy, actually, because eating food is something we all must do every day, and yet there is a wide variety of social contexts in which we do it, all of which have varying levels of expectation about the correctness and formality of our behaviour.
Now, about table manners. We don't expect the same level of formality at a family picnic that we would expect to see at, say, an embassy ball. Nevertheless, there are certain basic standards that most people apply to a family meal in the home. We all know what those are.
Of course, if you were raised by wolves and don't know any better, your friends are going to cut you some slack here, although you probably won't be asked back to Nobu any time soon. But you will no doubt be able to enjoy many happy evenings at Pizza Hut and Swagman.
If you do know better, however, and behave like a pig deliberately, you are not going to win yourself any friends. Such behaviour is deliberate ugliness, of the kind which is often seen among groups of young men who haven't yet got over the novelty of having a penis. And if you inflict this kind of behaviour on your friends, you're not likely to be asked back even to Swagman.
Similarly, if you really are deficient in the English language, of course your friends are going to cut you slack. Many of my friends are not native English speakers. Sometimes their English is not quite perfect, as indeed one expects. And some of my friends are just not educated, and they cannot spell or use grammar to save their lives. Some warm and wonderful people are in this group, and I don't love them any less because their talents lie in other directions than literacy.
BUT - and this is the big But, the all-eating But. If you are going to call yourself a writer, there are NO EXCUSES. Because, you know, writing and stuff. A writer who misplaces apostrophes, who confuses 'to' with 'too', who uses 'lay' intransitively, must be assumed to fall either into the deliberate ugliness category, in which case his behaviour is hostile, or into the category of those who don't know any better, in which case he is hardly what can be considered a real writer. One case indicates hostility and the other dishonesty, neither of them endearing traits.