Think of it like its scaled based on time.
You go spend a night in a hotel in the next town over, to see a tourist attraction, to visit a friend, to see the view, it doesn’t matter. When you get home you feel happy, you spent the night somewhere else, you saw some new things.
Next time, you go on a 5-day road trip, spend the night at a friend’s house, or a hostel, and you explore the city, or enjoy the woods, again, it doesn’t really matter as long as it’s something you enjoyed doing. Now when you get home it’s a little different. You want to go back, not quite ready to go back to everyday stuff, you were just getting used to being away.
Now, you go on a 9-day trip, be it camping in the woods over spring break, a family vacation to the Caribbean, or a long awaited adventure to Europe. Again, all that matters is that it’s somewhere you really wanted to go, somewhere away from home that you’ve been waiting to see or do.
When you finally get home after this trip traveling somewhere, it’s different. Not incredibly different than the other trips, but just enough. You were away just long enough that you got used to it, being in that other place, seeing the things you’ve desperately wanted to see, the Eiffel tower, Niagara Falls, the Italian countryside, Sydney, New York City, whatever it may have been.
You feel sad that you’re home, and that sting lasts a little while. Maybe a week, maybe 4 or 5 days, depends on what you did of course, and yourself.
Take this shitty feeling of missing out, of leaving somewhere amazing, and multiply it up for how long you are away. When you get home you miss the people, the new sights, the new smells, the new sounds. All these sensations that you waited so long for, and then they are gone, and you’re thrown back home exactly where you were before, like a rubber band ripping you out of the world, and bringing you back to your home.
Imagine this after a month in a different country, two months traveling multiple countries, it just gets worse afterwards. It literally can cause crippling depression for a little while.
It rarely comes up in casual conversation. It’s the type of thing that comes up after talking to the person for hours and you’re both travelling and away from home and dread what’s going to happen when you go back. So you ask the other person how they feel, if they’ve ever felt that way. And of course they have.
Most people have felt this, but people who travel far and long feel it the most. It becomes just being sad after a vacation to being depressed for weeks after travelling for a couple months. It exists and it will happen to you, but it’s okay. Take it as it is, draw from it, write, think what you can do to travel again. You’ll never be able to avoid it, but you’ll at least be able to make it worth it.