Travel is a set of unique experiences that form unique memories. Part of what’s addicting and pleasurable is that it helps slow down the perception of the passage of time, among many other positives.
It’s also self reinforcing in that when you think back, you tend to disproportionately remember travel vs other experiences.
There’s clearly a lot more benefits than that, but it certainly seems like a significant factor.
There's a lot about travel that just sucks. Flying is horrible, especially now. Hotels are soulless. You're surrounded by people trying to take petty economic advantage of the fact that you're in an unfamiliar place. Things never happen quite the way they're planned, and while sometimes this produces serendipity, it's sometimes infuriating or even terrifying. Still, people are remarkably able to handle discomfort, pain, and even danger if there's a purpose to it. With travel experiences, there almost always is. Sure, you spent six hours in an airport because some reptilian airline executive saved a few thousand dollars by cancelling a flight... but you got there, and you got to see and do things most people, in human history, could only read about.
Travel itself isn't fun at all. It's the experiences that travel makes possible that are rewarding. The good recontextualizes the bad.
This is paradoxical in a number of ways. For one thing, putting too much prior effort into engineering the experience leads to high expectations and disappointment. "I saw the thing. Now what?" We often don't know in advance what will produce the true prize memories. For some people, this is infuriating, and they have coped by creating Instagram culture, where the focus becomes the mindless collection of digital images ("look at all the expensive experiences I can buy") that makes travel, far from an escape from our decadent and purposeless treadmill culture, an extension thereof.
Travel and "education" are the two forms of conspicuous consumption that are socially acceptable. Spend $200,000 on a car and people will make small penis jokes (as they should) behind your back. Spend $200,000 (or forgo earnings in an equivalent amount) to take pictures of yourself next to recognizable world monuments... and you're "worldly". Travel makes you more interesting, people say, and it sure can... but if it were always so, then why are the people who get to do it all the time, the rich, so uninteresting and so useless?
Ultimately, what distinguishes travel is not that the experiences are good or bad in different proportions than are possible in a more homely life, but that we have the cognitive machinery--an innate conception of story--that makes the negative experiences, even if they are in fact petty and pointless, tolerable in the context of what is gained by going through them. In office life, this doesn't exist. We spend so much time there, we know the unpleasant bits are not only unnecessary but utterly detrimental. Office life is never physically or cognitively demanding, but it is emotionally stressful, and furthermore it delivers absolutely nothing of value. The people who stole all the money sell a little bit of it back to you, so you can survive today and return tomorrow. So perhaps the lesson is not that travel is wonderful, but that today's working life is so atrocious that people will spend substantial proportions of what little disposable income the system has given them, not to have rewarding experiences (which are possible through, but not guaranteed by, travel) but merely to escape it.
YMMV.
Having to fill in bureaucratic forms and pick your nose on demand with a stick, probably not fun.
Hitchhiking? Long distance sleeper trains? Motorhome? Sounds great to me.
I'd get on a Soviet sleeper train if it just took me from my house back to my house via some rolling countryside with the provodnitsi.
Outlier example, but I mean, I think you'd be hard pressed to argue that flying on a private jet wouldn't be fun.