Yes or What?

"Is this thing cool or what?"
Have you ever heard someone say something like this? How did you respond? Yes... or What? That is what is so interesting about this question. Usually you find tons of Yes or No questions, but what about yes or what questions. What if your friend asked you that question and you didn't find it cool at all. Then you would just say "what." This is how the conversation might go.

"Is this thing cool or what?"
"what"
"I said Is this thin..."
"I heard you"
"oh"

So... Is this kinda interesting or what?