Dog training collar. What do you think?

I love animals and I'm sure some people are going to cry when I say this buuutttt. I've heard of people using the vibration instead of the shock and at first it is just as effective but dogs are smart and they quickly learn it's not so bad. I've seen one collar that is actually kind of cool. If your dog barks it vibrates. Then gets stronger if the dog persists. If the dog still continues to bark it eases into the shock which will also gradually get stronger if the dog continues. I think in some pet cases the shock collar is necessary. And just so people know. It's not that big of a shock. I know because before I used it on my dog I shocked myself with it to know if it was really going to harm my dog. And guess what?.. It's like a static shock. Just kinda scares you.