Chris Puls (of Dog Scouts) wrote an interesting article on warning signs in puppies that might signify a need to see a vet or behaviorist. I found it interesting and a lot of it made sense so I thought I would share. 
http://www.dogscouts.org/uploads/Does_my_puppy_have_a_problem.pdf
http://www.dogscouts.org/uploads/Does_my_puppy_have_a_problem.pdf