Sweating in a Crowded Room
The human body obeys the laws of thermodynamics. Consider the experience of being in a small crowded room with lots of other people. In all likelihood, you'll start to feel very warm and will start sweating. This is the process your body uses to cool itself off. Heat from your body is transferred to the sweat. As the sweat absorbs more and more heat, it evaporates from your body, becoming more disordered and transferring heat to the air, which heats up the air temperature of the room. Many sweating people in a crowded room, "closed system," will quickly heat things up. This is both the first and second laws of thermodynamics in action: No heat is lost; it is merely transferred, and approaches equilibrium with maximum entropy.