In an ideal world, where all dogs are well-behaved, where all owners are responsible and fastidious about cleaning up after their pets, the dog park is a wonderful place for both man and beast. Dogs get a chance to play and exercise, while their owners socialize in a healthy outdoor environment. What could be better?
Along with my dogs, I've enjoyed many a good time at the local dog park and loved nothing more than to see my dogs play and deplete their pent-up energy. I'd guess that happened 99% of time, but that other 1% -- a holy nightmare!
A few unwarranted fights with untrained, unsocialized dogs that had no right to be there and I wasn't so hot to trot on the dog park gang anymore. Nonetheless I cautiously continued to go to the park until the inevitable happened. One fine day a crazy Dobie went after DJ, all 22 lbs of him. Fortunately, I always leave a leash on my dog so in the event of a skirmish I can yank him out safely. Because of that leash I was able to pull away DJ safely and unharmed from the unbalanced Dobie.
Talk to any good breeder and they'll warn you against the dangers of the dog park. I'm not saying avoid those parks at all costs, although now I do. I'm saying take heed, be aware, all it takes is one bad incident for disaster to ensue.
Ultimately it's your choice, you know your dog, you understand the dynamics of the dog park. Just don't expect to find me there with DJ again. There, I've said my peace.