To help a puppy get over biting and mouthing humans, consistency is most important. If someone in the dogs home lets them do this, then that will set you back. If they are starting to mouth you, give them an appropriate toy to play with. If they bite you, my favorite trick is the high pitched yelp, followed by turning my back briefly. You can also give them a very brief time out if they don't stop the behavior.

With Bulldogs it is best to realize that even though they are strong willed and stubborn, they are equally distractible and goofy. Often with a bulldog is being stubborn, like on a walk, I will be silly and they will forget why they were being stubborn and follow me:) Keep them cool when it is hot, don't over exercise them, keep their wrinkles clean, and don't leave them unsupervised. They are like dinosaur toddlers.

I would say the most stubborn breeds of dogs come from the Bully Breed. My top picks would be Mastiffs, French Bulldogs, and Bulldogs. So cute, but SO stubborn.

I too agree with the above answers. I will give a wary dog space and go about my business. I will keep calm around the dog and eventually I will try to give the dog a treat or set one close by and walk away. They generally warm up pretty quickly when they realize I am their person for the time being. I have had a couple dogs in the years past that were unfortunately mentally unstable, near the end of their lives and actually violent. In those situations I did the best I could to take care of their basic needs and protect myself. It also helps to be a goofy dog yourself. I often will mimic happy dog body language, that usually perks up a wary dog:)