There are actually, in my experience, two giveaways for crummy screenplays or teleplays. The first is the extent to which characters address each other by name. If  you’re writing dialogue with no ear for actual speech, it sort of makes sense to put down lines like “This isn’t about the money, Brian,” or “I long to see you, Ellen,” or “Let’s get one thing straight, Henry,” but that’s not the way real people talk.

The other tell is a three-word crutch. A search for it yields 1,940 hits in the screenplay database of Drew’s Script-O-Rama, starting with the comedy Wedding Crashers, where characters utter it six times:

• “Oh my God, yeah, she will.”
• “Oh my God. I’m so sorry.”
• “Oh my God, in front of all of ‘em!”
• “Oh my God, you didn’t hear.”
• “You’re cheating! Oh my God.”
• “Oh my God, don’t ever leave me.”

Second is the cheerleading movie Fired Up, where we find:

• “Oh my God, that bitch.”
• “Oh my God. My husband.”
• “Oh my God. Are you coming out to me?”
• “Oh my God, this is so good.”
• “Oh my God.” – “What?” – “Don’t move. There’s a bee on you.”
• “Oh my God.”
• “Oh my God, Diora’s right. My left side is weaker.”

Now, this is admittedly different from the characters’-names thing. People really do say, “Oh my God” — especially, it could be argued, people like the characters in light entertainments like Wedding Crashers and Fired Up. It has even more verisimilitude  in the smart teen comedies Clueless (1995), where it appears 14 times, and Mean Girls (2004), which has 10 “Oh my God”s.  The trouble is, post-Mean Girls, it’s been too much of a cliché to be of much use, even as a way to depict teen girls’ talk. Back in December 2004, “Molly Polo,” a contributor to Urban Dictionary, defined “Oh my God” this way: “2004: verbal fashion accessory used by the mindless. 2005: so over.”

When put in the mouth of a character of any age, “Oh my god” reveals the cinematic sin of telling-not-showing. The moviemaking hasn’t succeeded in communicating that a moment is shocking or dramatic or amazing, or that a character is experiencing strong emotion, so a line of dialogue has to spell it out. This failing is especially notable in lame action movies. Consider this passage from Transformers: Revenge of the Fallen. (Script-o-rama’s transcripts often lack characters’ names, so we can’t be sure who is saying what):

“Oh my God” is one of a number of phrases–including “Oh God,” “Dear God,” Good God,” and just plain “God” — that, over time, migrated from religious to secular use. As this Google Ngram Viewer chart suggests, “Oh my God” started catching on (in print sources) in the mid-1960s. Coincidentally or not, a 1966 Esquire’s cover illustration of an article by John Sack consisted of a quotation from an American soldier on a search-and-destroy mission in Vietnam: “Oh my God — we hit a little girl.” Another key moment was 1982, when the phrase was used in Frank Zappa and Moon Unit Zappa’s seminal recording “Valley Girl.”

I guess you could say the recent history of “Oh my God” is the change from the horrific death of a little girl to a realization that one’s left side is weaker. Certainly, the power had been sucked out of it by the 1990s, when it became part of the South Park catchphrase “Oh my God, they killed Kenny.” (Significantly, according to a wiki devoted to the series, the last time the phrase was used was in 2003.) The popularity of “Oh my God” led to one-word representations, such as a line from an episode in the first season of Buffy the Vampire Slayer, in 1996: “Ohmigod, Xander … what happened?“ And, of course, it eventually wrought the initialism “OMG,” the Oxford English Dictionary‘s first modern citation for which is from a 1994 discussion on a Usenet newsgroup about soap operas.

I’d say “OMG” still has a some script-juice left. I recall an episode of 30 Rock where Alec Baldwin’s Jack Donaghy used it in a conversation with Tina Fey’s Liz Lemon. The layers of irony and satire were fun to pry apart. But stick a fork in “Oh my God.” What Molly Polo discerned back in 2004 is, if possible, even truer today: It is so over.