OK, don't get all huffy. You can go to these places alone if you want to. I'm sure plenty of people do. Actually, I know it.
But what I'm saying is that there are some cities and countries around the world that are better to experience with company.
Some are more fun with friends. Others are safer with company. Others are just designed for couples.
Regardless of the reason, if you're heading to any of these places, it might not be a bad idea to talk someone into coming along with you.
Queenstown is party town. The restaurants are great, and the bars are even better. Many a ski day has been skipped at Coronet and the Remarkables due to a Queenstown-induced hangover. But if you head to the Kiwi adventure town on your own there's every chance you'll miss out on that completely, especially if you don't stay in a hostel (and thus have less chance of meeting like-minded solo travellers). I was even told by one restaurant that they don't do tables for one. I'll just eat in my room, shall I?
I love Moscow – absolutely love it. But the Russians can be tough nuts to crack. They're not the sort of people to immediately take a stranger under their wing. What that means is that if you're travelling solo, it's unlikely that you'll make many local friends, especially when you throw in the language barrier. Take a buddy of your own, however, and you've at least got someone to talk to. And get a smile from occasionally.
Las Vegas, USA
This is like Queenstown, but times 10. Visiting Las Vegas without a friend would be about as much fun as visiting Alaska without a jumper. Unless you count the sad sacks playing the pokies on their own all day, no one seems to go to Vegas without some company to get a little crazy with. We're talking pool parties, nightclubs, go-kart races and shooting ranges. Vegas is about letting loose – and that's not much fun to do alone, is it?
There's an unfortunate little caveat to this one: while the political climate is not the best right now for anyone to be travelling Egypt alone, it's particularly bad for solo female travellers. It's the constant hassle you get – the sort of behaviour that's borne of the seemingly widely held belief in Egypt that Western women don't need to be treated with the respect afforded locals. Maybe I'm wrong (I haven't experienced it, for obvious reasons), but Egypt looks a tough one for solo women to me.
Italy is a country designed for sharing. It's about sharing food. It's about sharing drinks. It's about sharing time with family and friends. There's nothing wrong with visiting Italy alone, but you do get the feeling that this is an experience that would be far better with company – someone with which to make la dolce vita even sweeter. Otherwise you end up drinking a lot of wine alone (although that's possibly just me).
San Sebastian, Spain
It's like a combination of Queenstown and Italy – a party town with great food and wine that should really be experienced with company, whether that's good friends or a partner. This isn't a place of particularly good museums or interesting monuments. It's all about eating and drinking, so unless you particularly fancy the idea of standing around in a packed bar yelling, "How good is this food!" at no one in particular, don't try to fly solo in San Seb.
These Pacific islands are stunningly beautiful, endlessly romantic, and just the sort of place you'd like to take your significant other to. And that's what people do. Most of them, in fact. Perhaps aided by the fact that this isn't a destination in the price range of most dirty backpackers, French Polynesia is littered with sickeningly happy couples getting their smooch on, and little else. Do yourself a favour: take someone with you.
Papua New Guinea
A few people on Twitter helped me out with this one, as I haven't actually been. But PNG, by all accounts, is a scary place (the cities, that is – I'd jump at the chance to visit the outer islands for some of the world's best scuba diving). As most travellers know, it's about strength in numbers in dangerous cities. One person is a target, while two or more people at least give the bad guys pause to consider what they're about to do. Walking the streets of PNG, I'd want to have a few friends around me. Or a bodyguard.
Which places would you avoid visiting on your own?