Shock Collars Not A Good Device for Dogs

You may know someone that has a noisy dog that tries to keep their pet quiet by using a shock collar.

There are two types of shock collars, one controlled by a person and one that reacts to noise. Are they safe for your pet?
The U.S. Center for Veterinary Medicine says that shock collars can produce "possible personality adjustment injuries".
Shock collars that react to sound do not always go off from a dog's bark, they an go off from loud noises near the animal causing distress.

The collars have also been known to cause "depression, eating issues, burns, displaced aggression and health issues that include heart and blood pressure problems" in some cases.

What are your thoughts on shock collars for dogs?