Except that "Heard It Through the Grapevine" is way more irresistible to my ears (and to many others'; I'll wager that the song has gotten far more plays over the years than "Sugar Sugar"). And stuff in a different mood - Kelly Clarkson's "Because of You," the Rolling Stones' "Satisfaction," Whitney Houston's "I Will Always Love You" - were pop hits, as I recall. What's the perfection in "Sugar Sugar" that's somehow lacking in "Because of You"? I suspect that you'll agree with the point I'm making. How are the other pop HITS of the day imperfect pop compared to "Sugar Sugar"'s perfect pop? The trouble with the phrase "perfect pop" is that it's trying to act as an explanation as well as a designation. E.g., "Sugar Sugar" hit because it's perfect pop, but what differentiates perfect pop from the other songs that also hit isn't that it hit (for whatever reason) but because it's, you know, perfect pop.