Yes after years of study and millions of dollars in grant money it has been determined that happy dogs wag their tails predominately to the right and when nervous predominately to the left.....This follows up on a study before it that found that dogs turn their heads to the left when looking at an aggressive dog and to the right when looking at a happy dog.....I think they should seek funding to determine if a dog prefers to stick it's tongue to the right or left when panting, what say you...??
http://www.bbc.co.uk/news/science-environment-24746107