okay...interesting info so far, mostly from mom...but that's to be expected!
again i say, i must have gotten lucky and gotten our Labs from good breeders with good intentions for the breed. You've all seen the pics posted. Our female is more sleek and not at all blocky even though she weighs 70 lbs. ( I swear we have her on a diet with more exercise and she's staying the same! lol) Our male, however, is more blocky and weighs 26 lbs at 11 weeks!!! I didn't do it, I promise. He was big when we got him...so don't yell at me if you're thinking about it. He is big boned and blocky...just like his mother, father and older brothers and sisters.
Neither of our Labs is agressive. They play with each other like puppies (even though she's almost 2), no mean growling/barking, no snapping...just normal, well adjusted Labs IMO. Gunner (the puppy) is still in his chewing phase and they'll both growl if you play tug-of-war with them (he does it more than her)....but again, nothing agressive or overly dominant from either of them.