Do you remember "Dear Prudence" by John Lennon? It was one of my favorites at that time, and I used to sing it by the campfire or whenever an opportunity arose. I had it in mind when I wrote "Joy". A song about the subject - and a girl as well.
There are two more strange ladies hidden in my lyrics collections:
"Vanity", whose lyrics I wrote after visiting the "Kunsthistorisches Museum" in Vienna where a section about allegoric paintings and sculptures had caught my attention, and
"Violet", that I wrote after a pleasant walk in the woods in spring