In a cantilever beam with a rectangular cross-section, the shear stress formula SAy/bI indicates that at the neutral axis, y is zero, leading to confusion about shear stress presence. It is clarified that while normal stress is zero at the neutral axis, shear stress is actually at its maximum due to the opposing forces on either side. The discussion emphasizes the importance of understanding the variables in the shear stress equation, particularly the distinction between the area A and the distance y. The correct interpretation is that y should be measured from the neutral axis to the centroid of the area being analyzed. Ultimately, shear stress is significant at the neutral axis, requiring careful consideration in structural analysis.