Sometimes dogs shake their heads because its collar isn't sitting right or itches under it..or because their ears itch or are uncomfortable.
no the dog must be drunk and is trying to pull it slef...
There is a surplus population of cats and dogs. No one is willing to take care of them, so to keep them from running wild in human-populated areas (which can be a health hazard because of diseases...
So you can have a friend.
So you can have someone to watch you place while you are gone.
Good playmate for your kids(if you have any)
So you can run off in laws.
Getting a dog.
Protection,...