Here's some stuff about labs that's not listed in the
American Kennel Club's breed standard:
Labrador retrievers are one of the top 10 "favorite" dog breeds in America. Even so, there is a theory among dog people which suggests that Labs grow up into such sweet, mellow, all-around tremendous pets in order to repay their owners for not having killed them when they were puppies. Most dogs reach social maturity between the ages of 16 to 24 months. Not so for our dear labs. They've got big adult bodies by the time they're 10 months old, (80-100 pounds, sometimes!) but goofy, puppy-esque brains until they're 30 to 36 months. (Of course this is not true for every single Labrador Retriever in the world.)
So they have extended puppyhoods, during which, they have a reputation for being powerful, impressive, single-minded chewers of things. Non-food things. Things like wood. And walls. And furniture. And smaller non-food things that end up requiring $1200.00 foreign body removal surgery. (Gravel. Socks. Pantyhose. Collars.)
Labradors are also more prone to hip displaysia than some other breeds. If you're going to purchase a lab puppy from a breeder, make sure said breeder is a decent one that has his or her breeding stock's hips certified by the OFA. (Orthopedic Foundation of America, I think.) Hip displaysia is a malformation of the ball-and-socket joint that makes up the hips. It becomes painful over time, and in fact can produce lameness, and even paralysis. Hip replacement surgery is available and the success rate is high, but so is the price tag. Displaysia is hereditary, and displaystic dogs should absolutely not be bred.
Labs are good with children, other dogs, people, and basically everything else. They are fun to train because they get a huge kick out of hearing someone say, "hey there, who's a smart doggie?" even though at times (especially before they're about 2 and a half years old) they're a little slow on the uptake.