As everyone might expect, the fact is applicable to a boy hating a girl and vice-versa, hence we have Jack (Ashton Kutcher) and Joy (Cameron Diaz) as the protagonists of the comedy. As the title suggests, the movie features some out-of –the-ordinary adventures, as only in Vegas can happen.  

In order for the two to hate, they obviously have to have antagonistic personalities, him, a slacker working in a furniture-manufacturing business who can’t persuade his own father (Treat Williams) to keep him on the job; her, a high-flying Wall Street commodities trader, obsessed with work and organization. Each of them suffers a shattering disappointment, Jack is given the sack, Joy breaks up with her fiancé (Jason Sudeikis), and each needs to escape New York. And the best way of forgetting is a wild night in Sin City, evidently.

The protagonists meet when they are given by mistake the keys for the same hotel suite and after a drunken night, Jack Fuller and Joy McNally end up tying the knot. This not being an extraordinary event to take place in Vegas, the two are determined to seek annulment of their rushed marriage. Only that they are tied by some ‘trouble:’ Jack wins $3 million at a slot machine with Joy’s quarter and both of them battle for the money.

Luck is not in their favor in court, where conservative Judge Whooper (Dennis Miller) declines to dissolve the union without “six months of hard marriage.” Therefore, the pair has to live like a couple, trying to work out their relationship. As there was no relationship to begin with, but lots of alcohol, the two will get along worse than cat and dog.

Joy has to move in with Jack in his sloppy bachelor home and will face the clichéd woman-man disputes related to the toilet seat or dirty laundry left all over the place. Moreover, the antagonistic personalities will engender frictions close to pulling off each other’s hair, to the great amusement of the audience. Commitment-phobic Jack meets and lives with obsessed-with-order Joy and they do nothing but drive each other crazy.

Whooper clearly stated that the couple must clear out their differences, however neither of them seems to have ever heard of trying. Their marriage counselor (Queen Latifah) fails to alleviate their dissensions, however their relationship begins to warm up when Jack’s family is charmed by Joy and her boss (Dennis Farina) clicks with Jack.

Written by Dana Fox and directed by Tom Vaughan (“Starter for 10”), the 99-minute long “What Happens in Vegas” hardly outstrips the success of the Judd Apatow romantic comedy machine. The plot and characters appear to be more at ease in the second 45 minutes; moreover, the cast perfectly fits all characters, even beyond the performances of A-listers Diaz and Kutcher. Jack and Joy’s close friends that accompany them on the trip to Vegas, Hater (Rob Corddry), respectively Tipper (Lake Bell) succeed in drawing bursts of belly laughs from the movie-goers.

Fortunately, “What Happens in Vegas” avoids the essential mistake that ruins even the best of movies, that is bad pairing. Diaz (“There’s Something About Mary”) and Kutcher (“A Lot Like Love”) hit it well on the silver screen, both in the hate and love scenes, highlighting that their popularity is legitimate.