Most dogs are inherently boorish and uncivilized so they don't know how to ask politely when they want to come back in the house and end up annoying their humans by scratching on the door and whining.
That's why dogs who have learned good manners should teach their uncouth cousins how to politely ask to come in like the dog in this video, who stands up and rings the doorbell when she wants back in.
-Via Laughing Squid