If you existed in the Sixties or Seventies, you wore polyester. Perhaps a stifling turtleneck, or plaid bell bottoms, or kid leisure suit, or Garanimals dress-up outfit that coordinated with your brother’s Garanimals dress-up outfit.
The double-knit variety is especially unbreathable, and the years give it a greasy patina. OK, not really, but in my mind it has a greasy patina, even after I touch it and am reassured that it does not.
I have come across lots of double-knit polyester yardage in thrift stores, and sometimes the designs are very cool. A lady in my quilt guild offered huge boxes of the stuff to anyone who would give it a good home. I stopped just short of the “reply” button. I do have a few pieces, but I wonder what to do with it. Purses, bags, sure. What else? The thought of wearing it makes me shudder, so no garments.