21 Jump Street

Lovingly ripped off from the late '80s / early '90s Johnny Depp-starring TV series of the same name, 21 Jump Street is the story of two rookie cops who, according to the script, look young enough to go undercover in a high school to investigate a new deadly drug that's killing teenagers. It threatens to be quite clever with some early post-modern metawaffle about the dearth of new ideas in Hollywood and knowing winks about stereotypes in high school movies, but then it forgets all that and goes on to be just another sweary comedy that's undeniably funny but a bit too long and is largely dependent on ye olde "characters behaving oddly while on drugs" LOLs that were popular in Shakespeare's day.

The film's single insurmountable problem is that the two stars don't look like high school students at all, they look like potatoes. One of them is even played by a man called Channing Potatum. Allow me to make my point with a hastily-photoshopped game of Spot The Difference:

Literally impossible to tell which are the actors and which are the potatoes, right? Hopefully what I've demonstrated here is that it would have made more sense to send them undercover in a greengrocer's or a supermarket or a field or somewhere else where potatoes are generally to be found. Because that would have made everything OK.