Jeff Gordinier is a Los Angeles-based journalist and author of X Saves the World: How Generation X Got the Shaft but Can Still Keep Everything from Sucking. A few years before he died, my wife’s father handed me a gift. More specifically, he handed me a blueberry that was covered in dark chocolate and infused with cannabis. My experience with mood-altering drugs remains curiously limited for someone of my generation (I’m 58) and provenance (I grew up in and around New York and Los Angeles in the 1970s and 1980s), but it was summertime at a cottage in California’s Laguna...