You weren't a nice guy. You were a complete wuss. And the girls probably picked up on your dishonesty.
You are probably right. The culture at the time (late 1970s) was that men needed to appear sensitive. Like Alan Alda in the MASH TV series. So as a teenager, I definitely faked it to some extent. Though I was legitimately on the “over-earnest” side. I really did want to please people. Even if it meant faking who I was.