British schoolteachers apparently think Courtneys are badly behaved, and I'm not surprised. Sorry, but Courtney: kind of a stuck-up name.
Based totally on my personal experience, I can see a Courtney being the kind of girl who makes the teacher's life hell by constantly talking, laughing, texting, and gum-chewing during class. She's not the class clown — that would be beneath her — instead, she's that girl who thinks she's too cool to pay attention. And who maybe feels kind of bad for the teacher because she has ugly shoes and is, like, teaching junior high school. She's the girl who's way cooler than you in eighth grade and who, if you ever actually become a teacher yourself, you totally dread.
While I'm sure the world abounds with humble, down-to-earth Courtneys, the Courtneys I have known have generally been princessy, popular, and blonde. The name doesn't say "bitch" to me exactly — Courtney's not the type to, say, fill your locker with tampons. She's the type to laugh when they all fall out, then go back to forgetting you exist. My friend from elementary school had a My Little Pony named Courtney, and it was the one nobody was allowed to touch.
Somebody once told me Courtney meant "of the court," as in royalty — but Anna H. thinks of Courtney as a "country-club name," so "of the tennis court" might be more appropriate. Wikipedia, however, thinks Courtney means either "from places called Courtenay in the regions of Loiret and Gatinais," or, more entertainingly, "snub-nosed." The name peaked in popularity in the 1990s and has since fallen off to #269 in the US.
As is often (shockingly) the case, the lives of famous Courtneys don't seem to bear out my personal biases about the name. Courteney Cox (note the extra e) basically seems like a nice person — she's been so helpful to poor lonely Jennifer Aniston, after all. And Courtney Love is a lot of things, but stuck-up isn't one of them. She's not the girl stuffing the tampons in your locker or the girl laughing — she's the one scrawling "BITCH" on her own locker and then incoherently tweeting about it. Interestingly, both famous Court(e)neys were born in 1964, well before the name hit its height.
I'm sure you guys know (or are) some nice Courtneys — but feel free to supplement my prejudices with stories of Courtneys who snubbed you in the cafeteria as well. It's never too late to relive the miseries of junior high, or to project those miseries onto otherwise innocent girls and women.