Why is Gilgamesh surprised by Utnapishtim’s appearance? What is Utnapishtim’s explanation for why he looks and acts the way he does?

Gilgamesh is surprised that there is nothing special about him, "I thought I should find you like a hero prepared for battle, but you lie here taking your ease on your back." I think Gilgamesh was surprised by Utnapishtim's appearance because he says "your appearance is no different from mine; there is nothing strange about your features." I think he expected Utnapishtim to be "a hero prepared for battle," which he was not.