2 Guns. It was fairly entertaining and occasionally funny for a cop/buddy/action movie. It starred Mark Wahlberg and Denzel Washington as (respectively) a Navy NCIS-type officer and a DEA Agent.
The biggest problem I had with the movie was not the stars, not the acting or direction, but the writing. It was lazy. The bad guy, played by Bill Paxton, was (wait for it) a CIA agent who was in cahoots with a drug dealer shipping drugs into the US to pay for CIA operations.
And I'm thinking "Come on, guys!" (I guess it was kind of sexist of me to assume the writers were men thinking women wouldn't write this tripe)(they were men). Take some stupid and paranoid conspiracy theory about the CIA and use it as a basis for your plot? I was almost waiting for the CIA to distribute crack in the 'hood.
This is just lazy writing. Instead of coming up with an original idea, they rehash an old, desiccated conspiracy. How often has the "CIA is evil" plot been used in movies and books and TV shows?
Don't be a lazy writer! Don't use overused plots, ideas, tropes, and cliches. Don't rehash decades-old ideas. Be original!
That extends to other areas of writing, too. Make sure your character development is strong. I know, I'd rather be writing a shoot-out or a car chase or a love scene but then you're not writing good fiction, you're making comic books. No, wait, that's an insult to comic books. You're writing stuff like 2 Guns.
Writing is hard work. You do it because you love it. So you want to do the best possible job you can. So, don't be lazy.