To be honest, there are several things that go through my mind, it all has to do with What, When, Where, and How?
I for one, do not have the slave/sub bound, He knows his place, and what he is to do when being punished. But when I am punishing him/them, I wonder if it is enough, does it make the point that they need to learn.
For me, that is the most impotant thing, of course I know depending on the slave/sub and his/her taste for pain, that 50% of the time, it is just a result of their own needs and desires.
Again, the point is to instill obedience, formost and utmost, not just the pleasure of the Mistress or dom.