Dogs get bored just like adults and children
Assuming that your dog is happy to just lie around all day or stay on it's own while you are at work could lead to a very unhappy animal.
While it's not possible or practical for most people to have contact with their dog throughout the day, due to work and other commitments, a dog will always be a lot happier if it knows that at the end of each day it will get the opportunity to go for a walk in the park or a run along the beach.
The stimulation that it will get from this activity and the time that it is spending with you will help it to keep a healthy mind and a happy personality.
This time together is all important for building the bond that will ensure you both get the maximum benefit from your relationship.
Quality time with your dog will reap rewards, just as they would with a child, with a more obedient dog who is happier to please you than to misbehave.
And a happier dog is a healthier dog that will tend to live longer and give you more years of pleasure.