What is the significance of Einstein's common sense quote in relation to his theories of relativity and quantum mechanics?

Einstein's common sense quote emphasizes the importance of simplicity and intuition in understanding complex scientific theories. In relation to his theories of relativity and quantum mechanics, this quote highlights Einstein's belief that scientific concepts should be accessible and understandable to everyone, not just experts. It reflects his approach of using common sense and logical reasoning to develop groundbreaking ideas that revolutionized our understanding of the universe.