There is no doubt that it is a joy to see a well trained dog. A dog that has been trained is well mannered and can be relied upon to stay calm in even the most distracting of environments.
Statistics also show that a well trained dog is far more likely to have a home for life, usually with the same owner. Well trained dogs do not tend to end up abandoned and living at the local rescue centre.
If we draw the comparison to any relationship in our life