The Happy Accident - cotton blend tie dyed camp shirt

I bought this shirt new online from a major site and have never worn it. It was supposed to be 100% cotton. It isn't and that was obvious as soon as I put it in some Procion dye. Synthetic fibers are not affected by this dye. My guess is that it's about 60% cotton and 40% polyester. How is any of this happy? When I complained I got my money back and I got to keep the shirt. It's a nice shirt, so I went ahead and finished tie-dying it for practice and to see how it would work out in the end. It's a a very nice pastel effect. I like this shirt because it reminds me of my cat, Dusty. She's a muted calico. Her colors are muted like this shirt. After I dye shirts in colorfast Procion dye they are washed once in Synthrapol and twice in unscented detergent that is formulated for sensitive skin.