Friendly dogs can cause injury
Did you know that injuries caused by dogs are not always a result of aggression (like a dog bite)? In fact, friendly dogs can injure people, too.
One of the first instances of a friendly dog hurting someone (that really sticks out in my mind) was back when I was a veterinary technician. We held a dog for a 10 day quarantine after it got excited, jumped up on a little girl and scratched her face,catching her lip and causing a tear that resulted in plastic surgery. Because this was an injury to the face - and in this instance particularly to a child - animal control took the incident very seriouly had the veterinary office get involved to house the dog for the 10 day rabies quarantine, which is a standard protocol with any animal injury, and also to give a behavioral assessment on the dog. It turns out he was a super sweet dog, but jumpy and easily excitable - a dog who was "overly friendly" and hurt someone because he jumped on people.
After that incident, I realized how much a dog's behavior can affect their potential to injure someone or not - and it has nothing to do with if they are a "good or bad" dog, but more to do with do they know how to behave, have believable boundaries, and consequences for actions. I know the owners of the dog in this story had most likely been telling their dog to stop jumping - probably for years - but the dog still did it! I suspect they also tried lots of things (like turning their back on the dog, asking him to sit, ignoring him, shaking a can of coins, even pushing out their knee) to see if the jumping would stop, but it never got better. Unfortunately, the reason he never stopped is simply that he did not have a consequence valuable enough to him for that action and consistency to make it stick. A conversation that mattered to him, in whatever form, that would correct the jumping was not had firmly enough or consistently enough for him to say - "ok, got it- no more jumping!" In addition, a dog like that probably didn't respect human space very much in other interactions either, like pawing for attention, climbing onto people on furniture, nuzzling and pushing into them, crowding folks as they ate, etc. All of these "pushy" things come from a lack of boundaries - and again, even if you're the friendliest dog in the world, you need to learn boundaries!
Otherwise, a friendly dog who doesn't have clear and consistent boundaries has the potential to (and these happen literally everyday!)...
- pull on the leash and could knock the handler over, breaking a wrist or arm because they saw a bird or squirrel, people, another dog, etc (this also goes for nervous dogs who are skiddish on the leash and zig zag around, tangling up the handler and knocking them over OR slipping out of their collar and running off)
- jump up and knock over a small child or elderly person causing then to break an arm, wrist, hip, or hit their head
- run out the front door and get hit by a car
- step on a smaller pet trying to play, breaking a leg or rib
- eat something in the house or out of the garbage that is not digestible and require foreign object surgery
- jump on the furniture knocking over frames, dishes, vases, etc. causing shattered glass and potential lacerations
- jump against windows and sliding doors, breaking the window and cutting themselves
- rush up to other dogs (probably dragging their owner behind them) over-excitedly and get bitten/attacked, which could actually create a fearfulness of other dogs
...and the list can go on and on. Having a well socialized and friendly dog is awesome, BUT if they are badly behaved and out of control can really get themselves and you into trouble. A little training, clear rules, set boundaries, and understanding that they are dogs (not babies!) can be the difference between including your dog in your life and enjoying it or constantly running behind them doing damage control! Be proactive, not reactive when it comes to your dog's manners and show them the rules of your world...otherwise they will make their own ;)Exercise control of your dog, in many avenues, so that they find your rules believable. If you or other people in the dog's life are not consistent with the rules and boundaries, your dog will be inconsistent, and when it's "show time" (people at the door, the front door blew open, a cat runs accross your path on a walk) there is a really good chance your dog won't listen to you. Be consistent and relevant when no distractions and excitement is going on and your rules stand a chance to matter when your dog sees something they want :)
P.S. this goes for dogs of all sizes, but especially folks getting puppies! They won't be bumbling pups for long... so please remember you're raising a dog, not a puppy and make your lives much easier :)