The Liskov Substitution Principle is a fundamental concept in object-oriented programming, ensuring that derived classes can be used in place of their base classes without altering the correctness of the program.

The purpose of life is not to be happy. It is to be useful, to be honorable, to be compassionate, to have it make some difference that you have lived and lived well.

你无法取悦所有人，所以不要尝试。