1. PUNISHMENT OFTEN FAILS TO STOP, AND CAN EVEN INCREASE THE OCCURRENCE OF, THE UNDESIRED RESPONSE. Since attention is one of the most potent rewards available, and since it is difficult to punish without paying attention to the offender, punishing may serve more as a reward than as a punishment.
2. PUNISHMENT AROUSES STRONG EMOTIONAL RESPONSES THAT MAY GENERALIZE. Once the strong emotional responses are aroused the degree and direction of generalization is largely uncontrollable. The result may be excessive anxiety, apprehension, guilt, and self-punishment.
3. USING PUNISHMENT MODELS AGGRESSION. The meaning of "social power is exemplified.
4. INTERNAL CONTROL OF BEHAVIOR IS NOT LEARNED. The offender may learn to inhibit the punished response during surveillance, but once surveillance ends there is no internal control mechanism to continue inhibiting the behavior.

Bibliography:http://www.oklahoma.net/~jnichols/PunishmentProblems.html