Need some input for artwork about horses

I've been commissioned to make one of my 3D collages that will be given as gift to a horse fan. I know some about horses in a superficial sense, but I would love to hear from some folks who spend a lot of time with them about the soul of a horse. What's important to a horse? What do they love? How do horses feel about people. Any kind of input would be greatly appreciated.

Here is a picture of the recent piece I made that inspired this request. I loved this stamp and wanted to build something around it.