( 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 does n'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 read and edit stories for grammar , style and substance , fixing errors is their job . In honor of National Grammar Day , 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 did n'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 do n't make spelling errors unless they just do n't pay any attention at all . Most people get verb tenses correct . And capitalization ... people love to capitalize things they should n'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 .
World Grammar Day is celebrated on March 15 . For copy editors , spotting errors and correcting them is their job . What are the best grammar and spelling fails you ' ve seen ? Share your news with @ iReport .