What's a little bad grammar between friends?

This post has been brewing for a while. In a couple of Facebook conversations about the importance of correct grammar, I've found myself in the strange position of arguing that grammar doesn't matter so very much. I say "strange" because I'm an editor by trade. A good sentence makes me ridiculously happy, and I'll willingly pull an all-nighter to put the polishing touches on a client's documents. One of my most exciting recent discoveries was that an em-dash is sometimes called a "mutton", and an en-dash a "nut". But it makes no sense to me to dismiss a person or their writing because they've got the grammatical wobbles.So, in true Gemini style, I thought I'd play both sides of the argument. And so as to avoid making a final call, I thought lists might be the way to go. 10 reasons why grammar matters1. Correct grammar is usually necessary — though not always sufficient — for clarity.2. A sound grasp of grammar, punctuation, syntax, and so forth shows that you are professional and have an eye for detail.3. Taking the time to write something correctly is a mark of respect for your readers.4. If you're lucky, a grammatically incorrect sentence might be ambiguous. If you're unlucky, it'll be stupid or offensive.5. If you understand how your language works, you'll find it much easier to learn a new one.6. Get control of your grammar and your writing can be so many things — elegant, stompy, fierce, light, outrageous, compelling, funny.7. Getting a sentence right is pleasing, and I'm all for cheap kicks.8. How else do you think word-nerds flirt with each other? The semi-colon isn't used as a winky face for nothing.9. Half an hour spent researching the finer details of an aspect of grammar or punctuation might just turn out to be the highlight of your day.10. Your grandmother might appreciate it. 10 reasons why it doesn't so much1. Focusing on grammar as the key marker of writing ability always seems to me to miss the point. Other reasons why your writing might be unclear include:·      you haven't structured your writing logically·      you're using too much jargon·      you'd need a spaghetti diagram to parse your sentences·      you don't know what you're talking about.Get those things right, and then we'll talk about grammar. Otherwise, it's like painting the windowsills on a derelict house. Or as food writer Nigel Slater says, "all fur coat and no knickers."2. Humans have a pretty robust ability to communicate. If we really need to say something to each other, we'll find a way. (Seplilng is nto etsnstail fro udnrestnading etihre, though it makes reading easier.)3. If you're talking in a language that you're not fluent in, it's likely that you're making mistakes. Chances are, you'll still be able to order lunch or make a friend.4. Have you talked with a three-year-old lately?5. Go on too much about other people's grammatical slips, and you start to sound like a snob. Read with generosity, and you might be surprised at what someone has to say.6. Nitpicking can make people feel anxious about writing. It's only Facebook. These people are your friends. If you don't understand what they mean, you can always ask.7. Sometimes one of your favourite authors will make a mistake. You don't want to let that distract you too much.8. Rules change, conventions shift.9. You can always hire an editor.10. If you worry too much about following the rules, you might forget to play.