It could be because they're bored, or it could be the smell of them that attracts them. Not all dogs chew shoes and when they do it's normally not the only thing they chew.
Dogs bite at your heels because they are herding dogs. These dogs see you as something that they want to herd. They use the same method when they are hearding cattle or sheep.
The main reason is that you have failed to train the dog correctly.
It's not good if your puppy does that as it is dominating behaviour and this could turn into aggression as the puppy gets older.
Because they love you.
I can give you several sentences.The fleas were biting the dog hard enough to make it yelp.She made a biting remark and hurt his feelings.Are the fish biting today?
All dogs require vaccination before biting my ankle.
Keep your dog inside the house
a biting purse
Dog muzzle
Pit Bulls
Have it professionally trained.
maybe
The best way to teach a dog to stop biting when he is playing is to tell them no biting. If they continue to bite them stop the play as a punishment.
Any dog can be "vicious" but its the owner who makes them that way. If you raise a dog right any breed can be a great family pet. Even if a dog bites it shouldn't always be deemed vicious, if a dog is biting out of fear then he is not vicious, he is protecting himself.
You may want to consult a vet to thoroughly check for fleas or ticks. Although scratching or biting is perfectly normal for dogs, obsessive biting could mean there is a more serious problem. check the spot where your dog keeps biting, and make sure there is no irritation or (tick, fleas, ect.). If you give your dog many baths it may just dry skin, try bathing less often or use a moisturising shampoo.
It is okay for your dog to play with your hands as long as this does not escalate to your dog being violent, which can be prevented by training your dog when to stop. Play biting is natural for dogs, so as long as your dog isn't really biting and your hands are being injured, then it is okay.