Queuing Theory is one of the fundamental tools for performance engineering. In this talk, we demonstrate some powerful applications of Little’s Law. Furthermore, some kinks and defects of the load testing tool is exposed via our exercise. Although Gatling.io is discussed, the type of defects are potentially applicable to other load testing tools as well. Finally, we seek help from our colleagues in CMG in trying to make sense a mysterious result that seem to defy common sense.