Magnet falling through a pipe (Lenz's Law in action)

This short video shows the difference between a metal ball and a magnet as they fall through a metal pipe or tube.
The metal ball falls freely with no visible hindrance from the pipe.
On the other hand, the magnet is visibly slowed down as it fall through the pipe. This is because currents are being induced in the walls of the pipe due to changing magnetic fields (the magnet is approaching and then receding from a particular section of the pipe).
According to Lenz's law, if an action produces induction currents, those current will have such a direction that they will oppose the initial action that created them. In this case the "action" is the pull due to gravity. This can be opposed by slowing down the fall.
Lenz's law is not an arbitrary law. It is an expression of the law of conservation of energy.
Imagine the opposite: what if those currents would help and support the action that produced them: this would mean that the magnet would be further accelerated so additional kinetic energy is created from nothing.