What’s up with beauty salons always doing this?

I just got my hair done and I told them na I wanted a trim with u-shaped layered cut. I even showed them an inspo pic that shows what I want because I have thick hair. When they finished, they ironed my hair which made it super flat, no volume and the “layered cut” were on the side of my hair lang but in the back it was so flat. I haven’t been to one beauty salon that cut my thick hair nicely, I always end up with straightened flat unvolumized hair.