Tolstoy famously said at the start of Anna Karenina:
All happy families are alike, each unhappy family is unhappy in its own way.
He almost got it right. It has many of the correct elements; families, happiness, unhappiness, and the powerful use of the word "all". It also was the exciting start to a famous and excellent novel. So naturally it is easy to be taken in by it. I too was once taken in by it. But "All happy families are alike, each unhappy family is unhappy in its own way" has one small flaw:
It is the precise opposite of the truth.
God knew this. God could have been cleared up the problem with this long ago, only, God sees the truth, but waits.
Just kidding. That's a little Tolstoy humor.
Here is what I learned finally from...life.
I am not famous. I am not Tolstoy. This is not the start of one of the most important novels in the history of literature. It will not guide you in life. It is not important. But it has one small virtue regardless:
It is true.
Happiness is different every single time.