Postulating that there is or was a Golden Age of fast food is kind of like asking which trip to the dentist is most enjoyable. Fast food is by nature devoid or mostly devoid of flavor, freshness, and health. If I did have to pick a time period though it would be before the advent of the mega chain places. Local ownership in the 50s, 60s, and even into the 70s meant a higher level of quality and a greater variety of choices.