Depends on who you show and from where, I'd say. Speculative reactions:
Aztec priest, Tenochtitlan, 1488:
"Maybe if we sacrifice some more people, we can stave this off...I mean...if we slaughter some more Tlaxcalan prisoners, maybe the age won't end and Quetzalcoatl won't enslave us and take our treasuries and make us worship two sticks...I mean...no...no...we sacrifice prisoners to stave off the end of the age, but...what the hell was Moctezuma thinking? And if our tributaries and caciques are that unreliable in the crunch...yikes. Just...yikes. I'm going to eat a prisoner's heart just thinking about that one..."
Ming dynasty bureaucrat, 1506:
"You lost me. So...merchants...merchants, mind you, not hostile nomads or feuding warlords like most times that kind of thing happens around here...are going to buy several small islands from us...rip off our technology and weapons...and then secretly control our government? That sounds kind of far fetched. It makes no sense...why wouldn't they just ride in on horseback and slaughter people or try to become Emperor themselves? And Japan? Those backwater Chung Kuo wannabe rubes on those islands on the other side of Korea? The part about the fat pedophile emperor who writes books of wisdom and has great posters of himself in every room and his battle to overthrow the unjust and corrupt thin bald usurper who worships barbarian gods and chases him to Formosa sounds a little fabricated too. And rockets with men in them being launched to the moon? You made this up to scare people in my province. Send this liar onward to Fujian or lock him up."
A Mughal courtier, Dehli, 1588:
"I knew there was something kind of fishy about those Portuguese merchants..."
King Philip of Spain, 1500s:
"I guess I figured it would be Moors or the English, not too much silver...sad. At least we keep Cuba and the Phillipines until that fat guy with glasses owns us in 400 years."
Tsar Ivan of Muscovy, 1552:
"Wait...why are you all getting so angry about this Stalin fellow? Right...but when people plot against you or disobey the boyars, you send them to Siberia. Its common sense. Yes, yes, but anyone who is ruler of Russia would be alert to such things, it is not paranoia. It sounds like he read some encyclopedia entry on me and just renamed a few things. The NKVD sound like my Oprichnicks and Beria sounds like a dead ringer for Malyuta Skutarov. Frankly, he sounds like my kind of man."
Sultan Suleiman of the Ottoman Empire
"Ouch. Electrodes? There? I guess that's the hard way to make a Janissary. Usually someone like this Saddam fellow doesn't make it past the first round of assasinations when a Padishah dies these days."
Christopher Columbus
"THEY NAME IT AFTER HIM?!! THAT LYING SACK OF SHIT! IT SHOULD BE NORTH AND SOUTH COLUMBIA! AW, MOTHERFUCKER. I WASTED DECADES OF MY LIFE SOLICITING MONARCHS, FIGHTING OFF MUTINIES AND IT WASN'T EVEN CHINA??!!! GOD DAMN IT!