How can I effectively reheat a hamburger to ensure it remains juicy and flavorful?

To effectively reheat a hamburger while keeping it juicy and flavorful, use a method that retains moisture, such as wrapping it in foil or reheating it in a skillet with a little bit of water. Avoid using the microwave, as it can dry out the burger. Heat it gently until warmed through, being careful not to overcook it.