The experience of case study tells us that legal theory is actually an abstract description of the practice of numerous and complicated life from a specific dimension, and it is impossible to follow, let alone discipline the complexity and vividness of real life. 
no matter how good the theory looks, it should not try to discipline the vividness, fullness and complexity of real life with its abstract propositions. Theoretical law scholars must always be aware of the limitations of the kind of discourse they are used to in the real life world, and can constantly understand the vivid legal world through the investigation of experience.
In legal work, you must be familiar with the experience of case studies.