One of the biggest challenges new pet owners' face, especially from shelter dogs is training. I would estimate over half of the animals turned into shelters are there because of some aspect of training.
This can include housebreaking, chewing, jumping, digging, growling, barking, pulling on the leash, and many other minor infractions the family has decided they simply cannot tolerate any more. The main thing people need to realize about most of these issues is these are normal dog behaviors. If these behaviors do not fit in your life, you must train the dog not to do them. If you don't, how is your new pet going to know what the rules are?
When many animals arrive at the shelter, the look of puzzlement on their face says it all. "What did I do wrong and why am I here. Where is my family?" They don't understand what happened and in most cases, it was human error to cause the dog to be turned in to a shelter, not dog error. They can't correct what they don't know is wrong.
Training is the most important task you can do for your dog. Please call your local shelter and find out about basic training. It could save a dog's life.