I don't personally believe in the "my dog is stubborn" label. I just feel that while all dogs will learn and do things differently dogs don't do things for spite on any level, and stubbornness is a level of spite in my book.
Commonly we find dogs that are labeled as "stubborn" are either not motivated properly or they are just not sure what it is that we want, sometimes they are pushed to their limits and want to call it quits so they come across as being obstinate.
Smart dogs are troublemakers but they are some of the best dogs in the world! Some dogs are so smart that it's quite difficult to keep the dog mentally challenged and they do all sorts of crazy things when they become bored -- chew things, eat things, become obnoxious with attention-seeking behaviors, bark, dig, lick . . . I could go on and on.
Most dogs are bred to do something specific or at least have some sort of job. As humans we don't often fulfill this to the degree that the dog needs and this is where I come in! Dogs do things they do when they are not mentally challenged enough and this is what we humans call "bad dog behavior". Most often it's insanely easy to fix, time consuming and some dedication may be involved but it's nothing you can't do.
A great way to challenge your dog is teach it to fetch and retrieve. Games and play are a remarkable way to bond with your dog and teach it how to use it's teeth on things appropriately.
Do you have a dog who loves socks? Well instead of yelling at him every time he steals a sock why not use this for a learning experience? My Border/Aussie, "Noah", was a little theif from the day I got him. I distinctly remember sitting back one day as he stole a sock and pranced off quite proudly and thought -- what should I do to make this easy on both of us and not a headache? It was the 4th sock he'd stolen that day. He was just 10 weeks or so and I can't tell you the joy in his eyes when he pranced off with those socks! His tail would be high and he was just ecstatic with his accomplishment. So it started that I began to teach him to bring things to me on command. Anything he picked up I'd teach him to bring to me instead of run off or have me yell at him to stop.
You can do this too. If you have a dog that has already gotten in trouble for stealing things then this will take a bit more patience on your part but it can be done if you can stick to it. Put your dog on a long line, about 15 feet. Put yourself in a room with socks, or something your dog likes to steal that he can't, or won't, tear up if he gets it in his mouth. The second he grabs the object begin to praise him. Yup. Go to town -- "Good boy! What do you have?!! Good boy!" He may do nothing, he may drop it and come to you, he may just walk off with it. If he starts to walk away give the leash a nudge and get him to come toward you. The very second he starts to come toward you with the object begin to praise him. Don't reach out to touch him or move your hands toward him at all as he may think you will take the object. Just verbally praise him, "Good boy! Gooood boy!" Every step he takes toward you keep praising him, or if he's looking at you. If he turns away or walks away stop talking. Get him to turn back and look/walk toward you and start to praise again. Continue this until the dog comes to you with the object and praise accordingly.
Here is a video of Noah bringing my dropped socks to me in the laundry room. I should have put my Jack Russell away as he was causing Noah to be in conflict about it but he still does it.