(CNN) -- — Going to a restaurant is supposed to be a relaxing experience. But for Katherine Dillinger, there was one thing that was guaranteed to stress her out: Seeing "Caesar salad" misspelled on the menu.
"It would just drive me ballistic," Dillinger said.
After years of practice, she's learning to relax. "Now, I just shrug it off. I still notice it, but it doesn't drive me crazy like it used to."
Many of us have a tendency to notice bad grammar and misspellings, as evidenced in the gallery above. But for copy editors, the people who to read and edit stories for grammar, style and substance, fixing errors is their job.
In honor of National Grammar Day on Tuesday, we sat down with Dillinger, one of the funniest grammar gatekeepers on the copy desk. She has been a copy editor for 15 years, six of which she's spent at CNN.com in Atlanta. The interview has been edited for clarity and brevity.
CNN: What made you want to become a copy editor?
Dillinger: I wanted to be a writer first, actually, but I took a reporting class in college and hated it. I didn't like going up to people, saying, "Your house just burned down. How did it feel?" At the same time, I was taking an editing class. It came easily, I enjoyed it, and it seemed like fun.
CNN: What are the most common errors you come across in your job?
Dillinger: Where to start? It's probably punctuation errors, specifically comma errors with independent and dependent clauses. Spell check means most people usually don't make spelling errors unless they just don't pay any attention at all. Most people get verb tenses correct. And capitalization ... people love to capitalize things they shouldn't.
CNN: What are your biggest grammar pet peeves?
Dillinger: Misuse of the em dash when you should have a colon instead drives me crazy! And I really hate the word "probe," just in general. I have a bunch, but those are my two main ones.
I'm constantly taking em dashes out of stories. Learn the colon! There are proper ways to use a colon. I shake my fist at you.
CNN: Could you ever be close friends with someone who makes lots of grammatical mistakes?
Dillinger: I used to date somebody who did, back in college. He was as bad a writer as you could get. I used to type his papers for him and edit as I was going. You learn to live past it, I guess.
CNN: Have you ever made a mistake? What's your most memorable one?
Dillinger: Oh, God, I've made so many. That's the nature of the business. When I was in Austin (on the copy desk of the local newspaper), there was a month where I just made one after another. It was terrible. It's your job not to do those things.
I've put incorrect information into stories. It kills you every time you do it, too. Luckily, none of them has been libelous or gotten me called up to the publisher.
CNN: What's the best grammar fail you've seen? Extra points if it made you laugh.
Dillinger: Where they misspell the team name on a jersey. Those always crack me up. It's not a grammar fail; it's more of a spelling fail.
CNN: The grammar rule that must never be broken is ________
Dillinger: You can make an argument that, within reason, you can break almost any grammar rule. You learn over the years that it's OK to break the rules. It's all in how you were taught. You go by what this story says to you. If this story splits an infinitive but it works, then I would split the infinitive! How the story sounds is sometimes more important than being totally adherent to every grammar rule.
CNN: How will you be celebrating National Grammar Day?
Dillinger: Every day is grammar day when you're a copy editor.
Is grammar really important to you? What's your biggest grammar pet peeve? All grammarians are welcome to discuss this in the comments below.
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