This has been a problem with my wardrobe as far back as I can remember - polyester makes me sweat.
So even a beautiful colour, comfortable, flattering garment has to be rejected because of the fabric composition. It's getting trickier to identify it too. I used to be able to touch the item and tell, but they are getting better at making soft, natural feeling weaves.
Example: I have a nice shirt that I got recently thinking it was that new bamboo fibre. It is so soft and drapes beautifully, some french design brand. But I wore it the other day and sweat buckets! I couldn't figure out what was going on because it wasn't THAT hot out. After I got home, I peeled it off and searched for the tag... it was very faded (2nd hand garment) but I finally saw the cause "100% polyester". It tricked me!
The thing is I still want it in my wardrobe. It's pretty -- AND its comfy -- a hard combo to beat. But I can't be sweating like that everytime I wear it, and I'm not a fan of antiperspirants.... sigh... it's gotta go. So sad. At least I didn't spend a fortune on it.
Like every rule, there are exceptions. I have 4 shirts, 2 dresses and one pair of black slacks that are a polyester/spandex blend because they have a very specific purpose. These are my travel clothes. They are wrinkle proof, pack VERY small, wash up and drip dry quickly and look fantastic on. Its worth the sweat for all those features when travelling. And worth the space they take up in my closet the rest of the time (yes they look THAT good). I got to take them to an out of town wedding just a couple weeks ago, I was the only one in my group that didn't need to iron in the hotel room before heading out.
Sometimes the convenience outweighs minor discomfort, but for day-to-day life the polyester is not welcome in my wardrobe.