Just left a dental appointment that had me wondering... Do you close your eyes or keep them open while dentist is preforming procedure?

Even after 3 and Aesthetics I still feel the coldness of his tool when he places it on the teeth and feeling the bottom of the teeth we go through and the root snapping off as it Glides up through the gum and you hear the popping sound when a tooth is finally removed. My dentist don't like me because I don't show no facial expressions he always asks me why don't you ever show facial expressions and I told him because I have a High excruciating pain for the tolerance that you give me LOL