What is the name for a feeling (name of facial expression much welcome too) you'd experience, when facing someone apparently believing an obvious lie or scam?
"So, imagine this, the guy who came to install Internet, he said for twenty bucks he can add Google to my package, so that I can search the web for free. And for another ten bucks he installed Wikipedia!"
I checked his screen. Indeed, there were two shortcuts on the desktop, one opening the browser on Google.com, and the other on Wikipedia.org.
"Did you really pay thirty bucks for two shortcuts on your desktop?"
If I want to replace speech in the last sentence with just a description of what appears on that person's face, how would you phrase that?