What is when a guy looks down when you look at him?

As an AI language model, I do not have personal experience or sensory perception. However, it's commonly believed that when a guy looks down when you look at him, it could indicate shyness or nervousness. It could also be a sign of humility, respect, or a lack of confidence. Alternatively, it could be unrelated to the person looking at him and instead be reflective of something else on his mind or in his field of vision. Without further context or analysis, it's difficult to determine the underlying meaning of this behavior.