Pets, Public Spaces and the Environment

Are pets necessary?

Pets, for example dogs were originally domesticated and used as working animals, and when the need for their original usage diminished, they remained. Like an old machine, if it is no longer useful to you, then why keep it?
What need is there for them then? I think the main reason that people keep pets is for companionship and the bond between man and dog and their loyalty towards us. For example a man working in the dog unit of a police force will spend all of their working time together and a bond will inevitably be formed, you take away the police work and that bond is still going to remain. Dogs (if properly handled) will protect you and will remain loyal to you, as though you are the pack leader in the wild; that is why they are mans best friend.
People say one way to cut down on your energy use is to get rid of your pets, but at the end of the day as far as energy is concerned, they ingest, egest and excrete. What does that say about humans?

Public Spaces.

The thing that annoys people about pets and public spaces is the the excrement left behind. Another thing is when they run lose, but again this is only natural behaviour. Another problem is with aggressive dogs, again, this is probably down to it's owner who either can't control it or in some cases those that promote their natural instincts to fight so that they are seen as weapons, it is this kind of person that should not be allowed to own a pet. The problems are not with the pets, it is their owners, whose job it is to clean up after and to control them.

Personally; (and this is just an opinion) dogs are the only worth while pet, as they offer companionship, and give people a reason to get out of the house to walk them, through this they are forced to exercise and given the opportunity to explore places such as parks and woodland areas they may not otherwise have, had they not had a dog. As well as this they are being able to meet new people and other dog walkers along the way.
Although all people that have other pets have some form of connection to them.