This is a nature documentary based on the 2001 non-fiction book by Michael Pollan. The movie discusses an interesting topic of breeding apples, potatoes, marijuana, and tulips. Each of the plants represents a human desire: for sweetness, sustenance, intoxication, and beauty, respectively. So how have humans affected the development of these plants and how they, in turn, have influenced ourselves? This documentary definitely should appear in your watch-list.