Songs I knew would be hits (I was wrong) department:
Both of these with a semi-Herb Alpert connection, since they are both by Sergio Mendes.
Sergio's first album with the revamped group Brasil '77 contained the gorgeous Paul Williams song "Gone Forever," featuring a sensuous vocal by Karen Philipp and a stunning Dave Grusin orchestration. It had Top 40 or at least AOR hit written all over it. It tanked.
Two years later, after Sergio left A&M for Bell Records, his first album there contained the great funky Lambert/Potter tune "Love Music," with great vocals by Bonnie Bowden and Mrs. Mendes, Gracinha Leporace, and a smokin', brass filled arrangement by Tom Scott. It wasn't quite the bomb "Gone Forever" was, since it charted on AC and "bubbled under" on the Pop charts, but it really should have been a major smash that spring and summer of 1973.