Women can be jerks, too. Everyone knows that.
And yet in the movies, the female schmuck is generally relegated to side characters. She's a friend. She's a villain. She's never the heroine.
In the outdated rulebook of who we get to see on the big screen, leading ladies need to be likable -- that tiresome, comedy-killing characteristic.
Thank goodness, then for Amy Schumer, the paradigm-busting, enfant terrible who's there to snap us out of our malaise with one rowdy gal: Amy.
Her vehicle, "Trainwreck," written by and starring Schumer, luxuriates in the idea of selfishness while shifting our antiquated ideas of what we want from a female lead, because, most importantly, it's very funny.
Bawdy, brash and beaming with confidence in every mistake, Amy does not suffer fools gladly or suitors at all.
As a young girl, her good time Charlie father (Colin Quinn) instills in her the idea that monogamy is impossible. Or, "monogamy isn't realistic" as he makes Amy and her even younger sister recite over and over after a conversation comparing partners to dolls.
It becomes her mantra. We meet up with her 23 years later, boozing and sleeping her way through Manhattan. Well, not sleeping. She never sleeps over at a man's place or lets them stay at hers.
Amy is pro-pleasure, anti-romance, and just a "modern chick who does what she wants" in gold lame miniskirts. She's a self-satisfied mess.
Her sister Kim (Brie Larson) has chosen a different route, marrying a sweet, dorky guy (Mike Birbiglia) with a sweet dorky son (Evan Brinkman). Amy pokes fun at them with caustic abandon.
Were it not for the great performances from Larson and Birbiglia, the ongoing finger-pointing at Kim's boring life might just come across as mean. Instead, they just accept Amy (with an eye roll).
Amy is a true jerk. She's selfish. She's rude. And she knows it. It's an interesting line that the movie skirts for the duration and a testament to Schumer that this mostly unlikable character remains enjoyable to watch.
She's is fun, but she's not nice or thoughtful. Nor does she want to be.
All this makes it particularly odd that for about 75 percent of the movie this freewheeling character is not only in a relationship, but she's in a relationship with a really, truly nice guy.
Amy's editor (an excellent, unrecognizable Tilda Swinton) assigns her to profile a successful sport's doctor Aaron Conners (Bill Hader) for "S'nuff," a men's magazine with "Vice" bite.
They meet, click, and get down to business after a drunken night out.
Pretty soon, and without much of a fight, they're subway kissing, Brooklyn Bridge-gazing, Central Park carriage-riding, and engaging in other cheesy rom-com tropes that are overlaid with a snarky, self-conscious voiceover from Amy.
The biggest surprise about "Trainwreck" is how conventional Amy's arc actually is. It's an eyebrow-raiser that might seem like even more of a cop-out if it weren't for the magnificent Bill Hader, charming and hilarious even in this straightforward role.
LeBron James is a comedic revelation, too, playing himself as a romantic-at-heart best friend to Dr. Conners.
With "Trainwreck," director Judd Apatow has triumphantly exited the depressive bubble that he found himself in with the earnest but flawed "Funny People" and "This is 40."
But, much like those films, "Trainwreck" feels overlong. The meandering third act brings the energy to a near halt, as the film veers into self-reflection territory. It also has one of the limpest movies within a movie ever.
And then Apatow sticks the landing with one of the most delightful, side-splitting closings since he "Let the Sunshine In" in "The 40-Year-Old Virgin."
If you're looking for something radical, you'd be best to stick with Schumer's television show.
"Trainwreck" is just good fun, and a lot of it at that.
"Trainwreck," a Universal Pictures release, is rated R by the Motion Picture Association of America for strong sexual content, nudity, language and some drug use." Running time: 125 minutes. Three stars out of four.
MPAA Definition of R: Restricted. Under 17 requires accompanying parent or guardian.
Follow AP Film Writer Lindsey Bahr on Twitter: www.twitter.com/ldbahr