thermodynamics - On a molecular level, how does heat transfer take place?

When an ice molecule hits a water molecule, the water molecule adds kinetic energy to the ice molecule. Why do the water molecules lose kinetic energy? In other words, why does heat like to go where there is less heat? I know thermodynamics tells us energy can't be created or destroyed. It doesn't really make intuitive sense, though. In the macroscopic world, if a ball hits a moving object in a non-opposing direction to the direction of force initially applied, the object's velocity actually increases, while the ball suffers from Newton's equal-and-opposite-reaction rule.