The television series Weeds, featured on Showtime, is a "dark comedy" depicting the life of Nancy Botwin and the choices she has made to support her family since her husband's untimely death. To make do, she decides to start selling drugs. Through various mishaps, she winds up moving to a fictional community near the San Ysidro border crossing to México where she ultimately becomes involved with a cartel kingpin who is also a prominent Mexican politician. She becomes increasingly exposed to violence and her own family is often at risk because of her decisions and associations. The Mexican characters on the show are depicted as corrupt and immoral, willing to do anything to further the drug trade. The insinuation of inherent corruptness and dysfunction proliferates much of the show, particularly when the privileged white characters constantly make racist comments about the Mexicans or "speak" in broken and offensive Spanish (e.g., adding o's to the end of English words to suggest that that somehow makes the word resemble Spanish).
This is quite problematic. The intention of the show may not be to reinforce negative or racist stereotypes but that is definitely one of the consequences. Though Mexicans as a group are not singled out (i.e., prejudicial comments are extended to nearly all marginalized social groups), it is still a bit excessive at times. Not everyone who is going to be consuming the show is aware of the ways in which certain statements or depictions may be incredibly problematic. Also, this type of humor has the tendency to codify and disseminate certain negative ideas that are not necessarily true. For instance, many people may not know much about México, but upon screening this series the idea that corruption proliferates all aspects of the governmental structure in ways which cannot even be compared to the United States is clearly articulated.
The point is that even when something seems funny, it can have very profound, negative effects and impacts. Humor can be used as a tool to tackle controversial or otherwise difficult to approach topics, but it can also (inadvertently) reinforce negative ideas and assumptions and diminish the possibility for individuals to exert their agency in productive ways (i.e., it becomes difficult to have to work against the negative stereotypes ingrained in the social imaginary when you belong to such a group).