This was written by Motown’s main production team, Holland-Dozier-Holland (Lamont Dozier and brothers Brian and Eddie Holland), and it reached No 1 in both America and Britain in 1966. The lead singer was Levi Stubbs, and group member Duke Fakir told the Guardian in 2014: ‘Eddie [Holland, producer] realised that when Levi hit the top of his vocal range, it sounded like someone hurting, so he made him sing right up there. Levi complained, but we knew he loved it. Every time they thought he was at the top, he would reach a little further until you could hear the tears in his voice. The line “Just look over your shoulder” was something he threw in spontaneously. Levi was very creative like that, always adding something extra from the heart.’
Here is a live performance from 1966.