My all time favorite reaction was when I took a trip to Naples, at a CVS, I had forgotten my wallet, but CVS is now using NFC, so I take my phone out and tap it against the terminal. This girl looked at me and completely flipped. She was saying how amazing that was and that she's never seen anything like that, on and on, all while pacing back and forth. Funniest moment ever, I will never forget it.
-Luis