You may have noticed that when you invite close personal friends of yours to a party they may be convivial and they may get along well, but rarely do friendships develop between your friends.
It was always my hope that my friends would become friends with each other but that rarely happened.
I gave a great deal of thought to my failure in this endeavor and came up with an explanation. It may be an explanation that makes sense to you too.
I am a somewhat complex person, like most people. My friends are attracted to me because of a variety of my personal attributes. They do not find that same attribute that attracts them to me in any of my other friends, necessarily.
That makes sense, doesn't it. I am like a starfish with each pod independent and different. My friends are attracted to different parts. They are not necessarily attracted to each other. Picture the starfish with a bunch of mussels or clams attached to each pod. Those mussels or clams might not be interested in mussels or clams on other pods.
Now, I realize that in-laws have the same complex quality.
My children, like me, are complex and the spouse they find is attracted to some attributes of my child that I may not have appreciated myself. The spouses may have significantly different attributes from the attributes in my children that I most appreciate.
The same can be true of lovers. The magnetic attributes between me and a lover may not be in any way related to the attributes that attract friends of my lover. So my lover's friends may be of little or minor interest to me.
All of which is to say that families are inherently diverse and can be difficult. Because of their long-term nature, it is incumbent upon sensible people to accept the diversity and maintain family equanimity.