It is very difficult to understand many concepts or even know where you are located right now without a reference point, which is a mark that allows you to compare or locate your position relative to external elements.
Our brain is a super computer that keeps comparing and evaluating everything around us all the time. Besides all the other things the brain has to do to keep us alive. So we actually are not aware of all the impressive processes our brain has to perform 24/7.
But as ironic as it sounds, Life gives us strange ways sometimes for us to compare and set new reference points in and learn our lessons, many times the hard way.
Sometimes you get tired of your own town, city, country, etc. So you decide to travel. Then you see new things, you meet new people with new customs, you try new food and so on. After a while, you begin to compare those new experiences with your home and then you begin to feel nostalgic and begin feeling the wish to go back.
And when you go back home, you feel happy, safe and with a renewed appreciation for those things you were tired of before your trip.
You had to get out of your daily routine in order to see the good in your regular environment.
The absence of routine was that reference point that allowed you to understand and appreciate what you no longer noticed, due to everyday monotony.