"What Happens in Vegas" is another entry in the endlessly growing line of cookie-cutter romantic comedies (which I lovingly refer to as "rom-coms"), predictable from its implausible beginning to its impossibly cheesy ending.

The filmmakers behind this particular rom-com were apparently a little bored, too, as they decided to challenge themselves by casting the two most obnoxious leads they could think of. I imagine the casting meeting went something like this:

Casting director: Okay, the goal here is to pick a male lead that we are confident roughly 80 percent of the country would like to punch in the face... names?

Rest of the room in unison: Ashton Kutcher.

Casting director: Done. Next, the female lead - we need her to be an actress that comes across as really ditzy even though she's playing an intelligent character.

Rest of the room, again, in unison: Cameron Diaz.

And that was it. A 10-second meeting. Meanwhile, across the hallway writer Dana Fox was meeting with director Tom Vaughan:

Fox: The script is done. It's perfect.

Vaughan: Hold on, the producers wanted me to ask you, 'Are the last 20 minutes packed with lines so cheesy that you were embarrassed just to type them?'

Fox: Oh yeah. There were a couple times when I said out loud to myself, 'That is the worst line ever written.'

Vaughan: Perfect.

So naturally, then, "Vegas" must be a horrible film, right?

Wrong.

Somehow, in spite of a plethora of valid reasons to hate this movie... I did not. Instead, it's largely an enjoyable rom-com. I feel dirty even saying it, but Ashton Kutcher was okay. And by "okay" I mean I was able to forget for 90 minutes about my desire to sucker-punch him. Granted, I suspect the reason for this was that he was opposite Diaz, who oozes dumb while playing smart.

The main reason "Vegas" is successful is the BFFs (best friends forever). Rob Corddry and Lake Bell, the BFFs of Kutcher and Diaz, provide most of the laughs and outshine their more highly touted co-stars in every scene they're in. Corddry, in particular, is in his element as the loser lawyer who loves to take his shirt off after two beers. Bell is good too, although she gets less screen time to prove it. The truth is that the dynamic between Bell and Corddry is far more interesting and funny than the one between Kutcher and Diaz. Props to Jon Stewart, by the way, who has now propelled Steve Carrell, Stephen Colbert (the 't' is silent!), and Corddry into the mainstream. The folks at "The Daily Show" know how to pick them.

Two final casting notes: One, Queen Latifah has perhaps the most pointless role in the history of pointless roles. Two, Zach Galifianakis (the bearded, pudgy friend) is a subtly funny actor and he proves that again here.

Finally, whoever made the decision to show a couple of scenes during the final credits deserves a bigger paycheck. After a final act that is so awful even Freddie Prinze Jr.'s presence would not have helped, all is quickly forgiven during the credits. It's here that we finally see the actual wedding night in Vegas, and guess who steals the scene?

And if there is still an ounce of doubt as to who the true stars of this movie are, there is one final snippet even after that. No Kutcher. No Diaz. It's just Corddry and Bell (with an assist from Saturday Night Live's Jason Sudeikis), and I agree with what the kid sitting behind me said. "Best part of the whole movie."

Hey, might as well finish strong.

• Read Carson's movie blog at www.juneaublogger.com/movies.