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.
It didn't feel like years after some time on the trip. More like I've switched whole reality, myself and everybody else. After some 2 months, life and reality back home was just a distant dream, too unreal to even consider seriously. Thank god it was before phones and wifi became so commonplace, it massively helped with that, writing an email once a week in some obscure internet cafe.
Coming back, it felt I've spent a lifetime away. Twice. Now I judge vacations on how it feels how long it lasted, the more it does the happier I am with deciding for it.