Dogs just wanna have fun
First let me say that I love the above image. "What are tails for, eh?" Notice how tightly that little IG is holding onto that tails; her back feet are off the ground. I could literally sit at the dog park for hours and watch the interactions. I really need to get my butt back to the park with my camera. After the shoot and back home looking at the photos I am often surprised by what I've captured. I can't always see expression while it is happening.
When you shoot dogs in action; you get the chance to stop time and see what you would have missed. We can't possibly see all the signs; dogs give each other signals the entire time they are interacting. Some signs are so small that you would never see them unless you are sitting watching. And then there are the one's that only a camera can capture.
Often when I'm going over images I will notice that the rough and tumble play may have been more than play for one of the dogs. Or one of the dogs may have been fearful and I didn't realize this until seeing the images. Of course it is hard to focus, shoot and see all the behaviors at the sametime so I see the behaviors when I open up my image files.
Watching as I love to do is extremely important at the dogparks. Unfortunately it is one of the human behaviors that tends to slip by the wayside. Many people pull up a chair and have a good ole chat session. They may or may not know where their dog is or what they are doing; not good. Going to the dogpark is a social event; for your dog and for yourself but you must watch your dog at all times.
I have seen way too many avoidable incidents at the parks; and the cause is guardians not watching. As your dogs guardian it is your job to make sure they are behaving or that they are not being bullied; no one else will do it for you. Dog parks are great places; they offer a great amount of different dogs for your dog to socialize with.
There are some places where dog parks are not necessary; places where there are many open field areas where you can let'er rip. But canine interaction is extremely important; especially when your dog is young. By interacting with other strange dogs your dog keeps up with their canine communication skills. They learn to read each other the way they were meant to and they learn to play nice.
If you are lucky enough to have lots of friends with dogs and a either a huge backyard or a field at your disposal then you'll never have to use a dogpark. But for most people a dogpark is the only place their dog gets off leash.