By now you might have picked up on the fact I love classic comedies. Another of my favorites is Animal House (1978) which brought us John Belushi and the beautiful Karen Allen (later of "Raiders of the Lost Ark  fame). That bit in Animal House where Belushi does the guitar smashing, well that's just priceless. And I thought that scene ought bring it home to you: turn your shoulders and you will "smash" your drive an extra 20 yards.
Most amateurs swing with their arms. Real power comes from your entire body, especially your lower (legs) and upper (back, shoulders) torso. That's that "core" everyone talks about.
Belushi turned his shoulders on that stairway. So should you.
Enjoy the game again,