Anna Karenina principle - Wikipedia
https://en.m.wikipedia.org/wiki/Anna_Karenina_principle
The Anna Karenina principle states that a deficiency in any one of a number of factors dooms an endeavor to failure. Consequently, a successful endeavor (subject to this principle) is one for which every possible deficiency has been avoided.

The name of the principle derives from Leo Tolstoy's 1877 novel Anna Karenina, which begins:

All happy families are alike; each unhappy family is unhappy in its own way.

In other words: happy families share a common set of attributes which lead to happiness, while any of a variety of attributes can cause an unhappy family. This concept has been generalized to apply to several fields of study.