A few others have mentioned this too.. the first thing I check is the fabric content on tees. I steer clear of 100% cotton.
I bought a couple from BR this season that are serving me nicely.

I'm going to vote for team cotton. In my experience, buying a high-quality cotton tee always reaps rewards. I already mentioned JCrew and Petit Bateau. Other good ones I've loved in the past are by Velvet, Rebecca Beeson, Ella Moss, and Park Vogel (the brand is defunct, I think, but j park continues to make them). Alternative Apparel also makes nice ones.

Interesting! I am with Queen Mum, Kim. 100% cotton is not a stable fabrication - and it's worse in a knit. I vote blend all the way.

I agree with a blend - preferably modal. Super soft and somewhat silky.