It would happen on every bus tour I worked on in Europe. Towards the end, with a few days to go, the realisation would dawn on all of the passengers: I'll probably never see these guys again.
After several weeks of travelling together, drinking together and, yes, sleeping together – living in each other's pockets, pretty much – it would be a hard thing for everyone to come to terms with. So the panic promises would begin.
Great travel friends don't necessarily make great real friends.
We'll swap email addresses. We'll friend each other on Facebook. We'll create a group; we'll stay in touch. We'll have a reunion in 10 years; no, in five years! We'll visit each other. I'll come to America; you'll come to Spain. We'll be friends forever.
It's not just limited to European tour passengers, of course – that's just the mass example, blown out of proportion by the amount of people on board and their proximity to one another. But a similar thing is happening right now in hostels and hotels and airports and train stations around the world: departing travellers promising to stay in touch; plans to recreate the high of travel companionship.
But you know what? It will probably never happen. You really will never see each other again.
And that might be for the best.
There's a scene in Before Sunrise – a movie that must resonate on some level with anyone who's ever zipped up a backpack and walked out of a door – when the two characters ponder their future after a chance meeting on a train and a night together in Vienna.
Rather than do the usual swapping of phone numbers and addresses with promises to meet, they float the idea of just walking away, of enjoying the encounter for what it was and never attempting to recreate it. They almost stick to that, too, and it's an approach I'm starting to think has merits.
You meet so many people when you travel, so many fantastic, interesting, funny, strange, inspiring people. In a perfect world you'd be able to hang out with all of them every day – you could call up the French girl and the Japanese guy and the Argentinean couple and go and have dinner with them tonight.
But you can't. Instead you have a whole lot of Facebook updates you can't understand and a longing to spend time with people you'll probably never see again.
And even if you could meet up, would it still be the same? I've made some amazing friends on the road but these post-travel meet-ups don't always go well. In fact they usually don't. Great travel friends don't necessarily make great real friends.
There was the American guy who came to visit me in Australia and who turned from the chilled out travel dude to the Yank who couldn't stop talking about how his home country was better. There was a very awkward beer in Barcelona with people I realised I didn't have any more in common with than shared memories.
And of course there have been a few notable attempts to recreate road romances back in the real world that have ranged from the fizzling to the disastrous.
Maybe it's best to just let all of these people go. Why not end your trip and go your separate ways and admit that this is it? We've met, we've had a great time, and now it's over. Remember it fondly and move on.
The group reunion plans, after all, will come to nothing. Of all the tours I worked on and travelled on, not a single one has managed more than a few people being together at the one time. You move on with your life when you get home; those BFFs from Europe will inevitably become nothing more than the authors of the poorly spelled Facebook updates clogging up your feed after a few months.
Within a year you're not even sure where you met them.
So what's the answer? Do you become a hard-arse when you travel, the realist who refuses to swap email addresses and rejects the friend requests in the name of moving on? Or do you indulge in the romanticism and dream with everyone else of catch-ups and reunions and best friends forever?
I started writing this believing the former. But I think I might've just talked myself out of it.
Have you reunited with people you've met overseas? Do you try to stay in touch with everyone or just let it go?