But the term "chick flick" is seldom qualified or quantified for us. Can the rules of chick-flickdom be codified? What follows here is my best attempt; I'm sure a more perceptive film critic could do a better job, and please feel welcome to add your own codicils in the "Comments".
1. Chick flicks feature actresses who are not too beautiful. I call it the "Meg Ryan" rule: any actress more beautiful than Meg Ryan can't make a living in chick flicks. Needless to say, Catherine Zeta-Jones would go broke if she had to act in chick flicks. Hit the bricks, Nicole Kidman, that porcelain skin and those long shapely legs won't do you any good here. Go make some more vampire movies, Kate Beckinsale. Cute is good. Pretty is okay. Beauty is not. Sandra Bullock, not Charlize Theron. Kyra Sedgwick, not Scarlett Johansson. And for you old-timers, Audrey Hepburn, not Sophia Loren. Chick-flick heroines must be "girl-pretty", a term coined by a buddy of mine. A woman is "girl-pretty" if girls think guys ought to find her attractive, but don't. It's easy to determine which girls are girl-pretty. If a woman were to catch her husband checking out pictures of Reese Witherspoon online, which is highly unlikely, she would compliment him for having good taste. However, if instead she were to catch him sneaking peeks at Jayne Mansfield's considerable decolletage, he'd get a lecture on the destructive effects of Internet porn. Reese Witherspoon is girl-pretty; Jayne Mansfield would have starved before landing any part in a Nora Ephron screenplay aside from evil villainess/bimbo. And the director would make certain to cover her chest.
2. Chick-flick heroines have usually been done wrong by a man. Divorced. Abandoned. Husband. Lover. Lecherous boss. Drooling teacher or professor. Mistreated. Or worse, underestimated. In "Legally Blonde", all bases are sufficiently covered by having an ex-lover *and* a professor/boss mistreat *and* underestimate the virtuous heroine.
3. Chick-flick heroines attract losers, but are not attracted by losers. However, sometimes the loser successfully conceals his losing qualities until the denouement. The scene where she tells off the loser is usually the second most important scene in the movie.
4. The chick-flick heroine is the smartest person onscreen and can usually see everything more clearly than any other character, except her own love life. Until she figures it all out. Figuring it out is nine-tenths of the plot.
5. Often the intelligence comes across as withering sarcasm, and only the virtuous male romantic lead is able to withstand it all stoically and with good cheer -- up until the scene where, against all odds, or reason, or good sense, he confesses he's fallen head over heels for the castrating termagant. Some chick-flick film makers like to propagate the myth that the bitchier the woman, the more virtuous and desirable the man she ultimately captivates. "You've Got Mail" and "Kate and Leopold" are chick flicks cast in this particular mold. A man would have to be out of his mind to be attracted to the protagonist feminist-castrator characters portrayed in these movies (played to perfection by Meg Ryan in her post-cute phase), but this sub-genre of chick flicks attempts to sustain faith in the existence of the hypothetical man who finds bitchiness irresistibly sexy. And why not? Somebody has to keep hope alive for the millions of women in Georgetown and San Francisco who imagine that they're just one apoplectic snit away from finding Mr. Right.
6. She's a brave woman facing the challenges of life on her own terms, and overcoming them on her own terms. She's almost always a professional of some sort -- usually a journalist or publisher or editor, or some other brainy profession that isn't too wonkish or geeky. If she is a techie geek, however, of course she's better at it than all her beta- and gamma-male geek eunuch buddies, who unanimously acknowledge her as "the best", even though it's effortless for her, whereas they've sacrificed everything -- social skills, relationships, a life -- to get where they've gotten.
7. The trappings of royalty never hurt. "The Princess Diaries" movies have proven that. Talk about effortless virtue.
8. It's great if the chick-flick heroine ends up marrying the rich guy (even better if he's royalty, too, but rich is usually good enough) -- but it's for love, of course. Everyone knows rich guys (and princes) are, in our egalitarian world, no more desirable than a sanitation worker -- but why take any chances? And be he a prince or rich businessman or idealistic lawyer, it's only after he acknowledges how puny he is compared to her, and how empty his life would be without her, that he wins the fair but choosy maiden. That's the first most important scene in a chick flick.
In my opinion, and for what it's worth, the best chick flick ever made was "My Big Fat Greek Wedding" -- but it broke most of the rules listed above. Except for rule 1.