The best breed of dog to be left alone is the Greyhound. Greyhounds are independent and content to spend time by themselves. They don't need much exercise, so they can easily be left alone without getting bored or destructive. They are also very gentle and quiet, so they won't bark or howl when left alone. Another good breed for being left alone is the Bulldog. Bulldogs are very laid back and calm, so they don't mind spending time alone. They don't require many exercises either, making them ideal for people who aren't always around to give them attention. Finally, Chihuahuas are another excellent option for those who need to leave their pup alone occasionally. Chihuahuas are small but brave dogs that can handle being alone without getting too anxious or destructive.