Before the internet, we had no idea that grammar elicited such strong emotions. But now, it seems like the grammar police are everywhere – at work, in your Facebook feed, even in your memes. For some, grammar policing is no more than an opportunity to show how well they paid attention in school: “everyone knows you can’t end a sentence with a preposition.” But for others, you’d think a misplaced modifier was grounds for capital punishment.

Although we think grammar flubs are forgivable in casual conversation, there’s really no excuse for these six most common grammatical errors in the business world. A word to the wise, before we jump in: this isn’t a rant about the importance of being “technically” correct in your copy. There are plenty of phrases that are grammatically sound, yet completely awkward and off-putting, and have no place in good copy (don’t say “this is a situation out of which you must get.” Say, “get outta there!”)

On the other hand, in great copywriting, you’ll find tons of sentence fragments and other technical faux-pas – and they can be very powerful.

The items that made this list are the most serious offenders that will make your business look careless or obscure your intended meaning. These are the mistakes that could legitimately cost you your next (or first) big client.

#1: It’s not “its” when it’s “it is.”

Confused? Then this one’s for you. The apostrophe in “it’s” is just like the apostrophe in “don’t” or “shouldn’t” – a sign that you’re looking at a contraction, which is essentially two words spliced together. “It’s” stands for “it is.”

However, “its” is a possessive pronoun, as in, “I gave my favorite coat its own hanger.” The hanger belongs to the coat – its hanger.

It’s clear why these terms get confused, since we sometimes see apostrophes in other possessive terms, like “Jessica’s house” or “Walmart’s produce department.” If you have trouble remembering this one, just remember: you can’t make “it is” into a contraction without putting an apostrophe in there – which means that “its” must be the other guy, the possessive pronoun.

#2: You’re your own worst enemy.

And a similar note, “you’re” is a contraction for “you are” – leaving “your” (you guessed it) as the only option for the possessive pronoun version.

#3: Comma usage.

It seems there are as many ways to misuse a comma as there are ways to construct a sentence, but here are the most common errors:

  • Missing comma. “Let’s eat mom!” Without the comma after “eat,” this reads like we’re going to eat mom, which is hopefully not the intention.
  • Comma overuse. If you’re hypervigilant about avoiding the problem above, you may err on the side of caution by plunking commas down willy-nilly – but don’t! The easiest way to tell if a comma is misused is to read your sentence aloud. If the comma provides breathing room in a logical place, as it does in this sentence, it’s probably safe to keep it. If it interrupts the flow of your ideas, leave it out.
  • Comma in place of a coordinating conjunction. When you have two independent clauses, they need to be conjoined with a conjunction like “and” or “but” (or even a semicolon) rather than a comma. For instance:
    • Correct: I did my first sales call, and it went well.
    • Also correct: I did my first sales call; it went well.
    • Incorrect: I did my first sales call, it went well.

#4: Misplaced, or dangling, modifiers.

A modifier is a word (often an adjective or adverb) that describes, or modifies, some other word. For instance, in “pretty house,” the modifier would be “pretty.”

A misplaced modifier (also called a dangling modifier) is one that obscures the meaning of a sentence because the modifier is too far away from the word it’s describing. For example, let’s say you think your mom’s gigantic Victorian mansion is creepy, so you write, “my creepy mom’s house.” Because “creepy” sits next to “mom,” it sounds like you think your mom is creepy – not the house.

The solution is to keep your modifiers close to the people, places, or things they’re describing. “Mom’s creepy house” is much better.

#5: Run-on sentences.

You’ve likely heard of a run-on sentence, but can you spot one? Contrary to popular belief, they don’t have to be a mile long, but they do always combine two or more main clauses incorrectly.

For instance:

  • Correct: The dog was scared, so he barked.
  • Run-On: The dog was scared he barked.

Fix run-ons by attaching these clauses with conjunctions (and, so, but, for), adding a semicolon, or separating them into two distinct sentences.

#6: Unnecessarily long sentences.

Keep long sentences to a minimum. Complex or highly passive sentences don’t convince your reader that you’re smart. While they may serve to bolster your ego, they’re doing nothing to bolster your bottom line. Keep it simple.

#6: Typos.

While typos aren’t technically breaches of grammar rules, they’re one of the most common mistakes in business and copywriting. A typo on an important landing page may cost you the sale – if you’re that careless in your work, how can a prospect trust you with their time and money? Further, typos in blogs and URLs can hurt your site’s searchability, and even lead to dreaded 404 errors and time-consuming 301 redirects. If you can afford it, hire a professional copy editor or spring for a premium Grammarly subscription. If you can’t, at a minimum, re-read everything you write once before you publish it.