None of what follows should keep you from traveling to any of these wonderful countries; all are well worth a visit (I know, I've been to many of them). Consider these warnings something to keep in mind as you would any good advice. Some are a little odd while others are simply fun. Note: Unless otherwise stated, all quotes come from the State Department's website.
England and the UK
Air rage warning: Air travelers to and from the United Kingdom should be aware that "penalties against alcohol-related and other in-flight crimes are stiff and are being enforced with prison sentences." I bet a lot of passengers would say, serves the bloody twits right.
Gun warnings: Most are aware of the UK's strict gun control laws and if you want to bring a weapon you'd better have a very good reason which you'll need to spell out in a formal application. Here's the tricky part: You must also produce "a letter of good conduct from [your] local U.S. police station."
Romance warnings: Con artists worldwide love the Internet but certain UK hustlers take it to a special level. A current fraud scheme "involves someone posing as a member of U.S. Special Forces who establishes a romantic relationship via online dating services, and then asks for money once that relationship is established." This may say more about the gullibility of Americans than anything else but the bottom line is, don't give money to strangers.
Warrior warnings: Apparently there are still some who find romance in the idea of joining the French Foreign Legion (its website boasts "a chance to start a new life") but as the State Department gently notes, U.S. citizens "should be aware that the cognitive and physical tests to join are extremely challenging." Translation: Despite what you may have heard, they don't take just anyone, and when you wash out, don't go looking to the embassy for a free ride home.
Download warning: The U.S. Embassy in Berlin says there have been incidents of lawyers for German media companies "aggressively identifying individuals who are illegally downloading copyrighted content and then billing those people 1000 Euros or more per incident." So forget that cute Munich cat video and save yourself the $700+ fee.
Easy money warning: Potential visitors should "view with skepticism any unsolicited invitations to travel to Ireland to collect winnings or an inheritance." File this under "Blarney."
Pub warning: The Emerald Isle has "tough drunk driving laws" (now before you jump on me for stereotyping, this nugget was uncovered by an employee of mine who proudly self-identifies as Irish-American).
Nature warnings: Watch out for occasional earthquakes. Fortunately there are no big fault lines near most major cities but there are a few volcanoes, too, like Sicily's Mt. Etna which "has been intermittently erupting since 2000." Before you say, "So what?" it's worth remembering that 2010's Icelandic volcano eruption caused the worst European travel disruption since World War II.
Thieves-with-flair warnings: Not all bad guys look the part so do not be "lulled into a false sense of security that well-dressed individuals are not potential pick-pockets."
Wildlife warnings: Crime is not a big worry in this Scandinavian country, but if you happen to visit the remote Svalbard archipelago (located midway between mainland Norway and the North Pole) you may run across unique hazards such as "polar bear attacks." Norway's official tourism site goes even further, warning visitors to avoid bear confrontations but if that's not possible, "always have a sufficiently powerful weapon at hand when traveling outside the settlements." Note: If heading to Norway via Heathrow, better review the UK gun warning.
Caller-needs-money warning: You don't have to visit Spain to get drained of cash by this scam. It begins with a phone call from your "grandchild" who says he's been arrested in Madrid and needs money but please don't tell his parents! Is that really little Bobby? Of course not, but the State Department says people fall for it. If in doubt, call little Bobby's parents.
Remember, next week it's our turn: What other countries warn their visitors to be wary of in the U.S.