My Dad never watched Star Wars, and this was back when it was almost inescapable. Given what happened when he took me to see The Black Hole, it's just as well! ;)
Circa 1990, I encountered a middle aged saleslady who apparently had no idea what Star Wars even was. And yet, she knew of Star Trek. That still freaks me out to this day.
There's a newspaper cartoon reproduced in "The Art of Star Wars" book, where two old geezers discuss the fact they are the only two people who haven't seen the movie. One pulls out a gun and shoots the other, proclaiming "Now I'm the only one!".