The fads that I remember most:
Fashion: Big bold colors & patterns, Hip huggers, bell bottoms, halter shirts, and Mini, Midi, and Maxi-skirts. Marshmallow shoes (white thick soles on different color suede shoes), Converse chucks, ProKeds (sneakers), and Platform shoes. Daisy Dukes, Earth Shoes, Afro hairstyle (the bigger, the better).
Activities: Streakers (people running naked in public from point A to point B), roller skating rinks, Pet Rocks.
Some of the sayings were: Do your own thing, Laid back, Can you dig it, If it feels good …do it, Groovy.
Dances: The Hustle and The Bump