The personality of a dog is flexible and indeterminate. Dogs can be exuberant or shy; friendly or hostile; fearful or bold; aggressive or passive or some combination of the above. These differences in personality may to some extent be determined by breed, or individual genetics, but for the most part it is based on how and to what extent each particular dog has been socialized.
For the health and wellbeing of your dog, training should really not ever be considered an option when owning a dog. Well trained dogs are more likely to be behaved and listen, be void of behavioral issues, be good in public, and are less likely to bite. Owners also have a much closer connection with the dog when the time is taken to form a relationship through training.
When you decide to get a dog, you are doing so with the expectation that your new canine companion is going to be with you for many years to come. But how many years, exactly? This is something that all prospective pet owners would like to know. The average lifespan for a dog is about 12 years, but this fact by itself tells you very little. In reality, there are a number of variables that will help determine how long the newest member of your family is likely to be with you.