Boredom. Dogs need mental and physical stimulation to stay happy and healthy. If they're bored, they may start to engage in destructive behaviors, such as stealing shoes.
Attention-seeking. Dogs are pack animals, and they crave attention from their owners. If they don't get enough attention, they may start to act out in order to get it.
Teething. Puppies are teething, and they often chew on things to relieve the pain. Shoes are a soft, chewy object that's perfect for teething puppies.
The smell of you. Dogs have a very strong sense of smell, and they love the smell of their owners. Shoes and socks often smell strongly of their owners, so dogs may steal them in order to be close to them.
A game. Some dogs see stealing shoes as a game. They enjoy the chase and the attention they get from their owners when they're caught.
If your dog is stealing your shoes, there are a few things you can do to stop the behavior.
Make sure your dog has plenty of toys and activities to keep them occupied. A bored dog is more likely to engage in destructive behaviors.
Teach your dog a "drop it" command. Once your dog knows the command, you can use it to get them to drop the shoe.