pull someone's leg

Origin

Imagine the bustling streets of 19th-century London, where a quick, mischievous tug on someone's leg could cause a momentary stumble or surprise. This small, playful act of physical trickery—designed to cause a temporary loss of balance—was a common, if minor, prank. It was a form of lighthearted deception, making someone believe something was happening when it wasn't, or causing them a fleeting moment of confusion. Over time, the literal tug faded, but the essence of playful deception and startling someone with a sudden, false premise remained. The phrase then smoothly transitioned from a physical act to a metaphorical one, describing the good-natured verbal trickery we now know as a friendly joke.