When shuffling through query letters, bad grammar is often a loud warning bell. Literary agents tend to be wary when reading material from the prospective, unpublished author. Nothing will make an agent drop a query into the reject pile faster than poor grammar.
However, incorrect grammar can often be utilized as a literary style. Nearly every accomplished author does so—to one degree or another. Sentence fragments. Abbreviated words. Missing punctuation. Misspelled words and incomplete sentences. Literature is abundant with poor grammar.
So, how then can you determine when to ignore all those rules drilled into you by your elementary school teachers?
What is your writing for? Writing is purposeful. You don’t pick up a pen and commit words to paper accidentally. Is this a blog? An academic piece? A query letter? A creative piece? Resume? Knowing your audience is a time-tested lesson in writing, so for formal prose, always go the safe route and edit your piece to perfection to ensure perfect, “proper” grammar.
On the other hand, for creative pieces, bad grammar can help the author illustrate his or her point. The form your writing takes should match its tone.
Cormac McCarthy is known for his stark, bare prose and his distaste for commas and other forms of punctuation, such as the quotation mark. His writing not only complements the often-bleak tone of his work, but also adheres to a simplistic style for the sake of clarity and rhythm. He believes that punctuation can often disrupt the flow of a sentence and is usually superfluous.
Hope this was enlightening. I encourage those interested to read more on the topic. Here are some semi-related links to check out on the topic of grammar: