If you like Robert Downey, Jr., then you will enjoy Less than Zero (1987). He gives a brilliant performance as a crack addict from an affluent family in Los Angeles. Based on a Bret Easton Ellis novel, it also features a gorgeous Jami Gertz. James Spader is fantastic as the drug dealer/pimp. Andrew McCarthy is the narrator that ties these figures together, but it is really all about the characters who orbit him in the decadent world of rich cokeheads in late 80s LA. Hashish highly recommends Less than Zero.

