These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Complete Monster: Eddie Kim, in his very first scene, he beats a guy prosecuting him to death with a baseball bat, taunting him about how his son will grow up without a father. Then, to kill the witness to his crime, he releases the aforementioned snakes on the plane, killing dozens of people without a twinge of remorse for either the passengers killed by an entire swarm of venomous serpents or any potential collateral damage for a plane crash.
Ham and Cheese: Many people were initially surprised at Samuel L. Jackson agreeing to work on a movie like this.
Memetic Mutation: Almost exemplified with Jackson's now (in)famous One-Liner: "Enough is enough! I have had it with these muthafuckin' snakes on this muthafuckin' plane!" The line was written by fans online and placed into the movie as an Ascended Meme.
Definitely mutation: The original line is played in the music video at the end.
The director initially wanted a more serious movie with "Snakes on a Plane" being a working title, but after seeing the title, Jackson requested to keep it and everything it entails. With all the free internet hype for a Ham and Cheese B-movie (and no interest otherwise), it was probably a wise decision as the original would likely fall into no better than So Okay, It's Average.
The song above is so god awful in the lyrics and video that by rights it should tank, but Cobra Starship are so self aware of how bad it is that given the tone of the film they pull it off.