I know polyester is bad. It doesn't breathe, it looks (and is) cheap, it feels hard and uncomfortable on your skin. However, I have quite recently purchased a reasonable amount of lovely blouses from the 1970s, and almost without exception, they are made of polyester.
Yes yes, nothing beats natural fibres. But compare polyester to something like linen while sitting on the train for an hour... With linen you end up looking like a frumpy sloth that doesn't own an iron. With polyester, all you get is smooth airiness, and okay, maybe the added bonus of feeling a bit sweattier than you'd like. Oh well. How can it be so bad, if it looks so good?