Be a friend and be there
Loneliness is a major problem for dogs these days. While some dogs cope better with solitude than others, no dog enjoys prolonged isolation. Resulting psychological problems can cause excessive barking, destructiveness and more.
Spending time together is the most important thing in a dog-human relationship. Be it engaging in fun activities or even just hanging out on the sofa and watching TV, companionship increases the bond between you and your dog, helps prevent behaviour problems and makes training a lot easier. Why get a dog and then condemn them to a lonely life in the backyard? It's just not fair.
If you do not have enough time to satisfy your dog's daily needs for companionship, consider a dog walker, doggy day care or leave your dog with friends or family. Better yet, change your lifestyle.