The craving for novelty.
I'm sure everyone at one point has wished they could meet someone exactly like them, and you were sure that if you did, you'd get along with them, probably form a really close bond over shared passions and preferences—but I'd beg to differ. I think if that ever happens, it won't last very long; I would give it around a month until both of you are mutually mentally tired of each other's company and begin to detach. Why? Because humans crave novelty in life; no matter how much affection you may have over something or someone, it starts to fade once it quenches the thirst it instigated. Your favorite food can make you nauseous if you consume it enough, your favorite show loses its magic after a good number of rewatches, this applies to everything we experience. To me, I think it's one of the most unfortunate side effects of being human—nothing is ever permanent, despite how much one would like to think so.
Think of a friendship that ended. Think of why that occurred. Maybe you grew out of it…maybe you lost touch…maybe hanging out with them did not fulfill you as much as it used to…these are all probable causes. This nature of us that seeks freshness is simple when it comes to immaterial objects but hard to overcome when it comes to real people.
My take on the analysis of relationships (with no real data, just my observations, unfortunately) is that a bond will last longer if both parties show growth; I know it's cliché, but hear me out—the reason for lost friendships, I think, over time is when one person changes and the other does not. Perhaps in the initial stages of that bond, you may have connected over something that one person no longer finds relevant to the new mental space they have acquired. In simple terms, the person that grows will get tired of the other because there is nothing new to satisfy the novelty they need. This is one thing.
Differences must coincide.
I'm sure you’ve heard of the phrase “opposites attract”; it's true, but not in the usual sense. By this, I do not mean that putting a criminal and a civilian in a room will ensure they will fall for their differences and bond over the lack in each other. A simple metaphor would be a puzzle piece: one puzzle piece can connect with another that is not similar to itself, but their lacks mutually satisfy the needs of the other; yes, there exist other pieces that may look different, but only one can fully connect with the other. The differences must be something of which you need but do not know of yourself. Our soul needs something to achieve satiety, but our path of life has not graced us with its presence. Such a substance is brought forward by someone else, someone to introduce you to things that eventually find a place in your heart, someone to push you to limits you didn't know existed.
This is why some relationships endure and some fade; it isn't about whether it feels stronger in the beginning, but whether it continues to move in tandem with time.
This is why it is easy to not get tired of the sky’s beauty, because it is not the same each day; it's never stagnant.
