We all dream of a world where we can let our dogs off leash to run freely.

But, not all dogs are friendly. If your dog approaches an aggressive or fearful dog, this could be a very dangerous situation. All dogs should be able to enjoy a walk without the fear of this situation occurring.
On the flip side, your overly friendly dog approaching a timid pup could reverse a lot of work that owners/trainers have done. Not all dogs enjoy another dog running up to them, friendly or not.
Sometimes all it takes is one negative encounter to severely affect a pup forever
We have to be respectful of other people as well. Not all people are dog people, especially small children.
I personally have had many poor experiences with out of control, off leash dogs, which is why I am sharing this.
If you want your dog to be able to be off leash, consider working with a professional trainer and make sure that recall is fire!
There are many ways to give a dog more freedom while still using a leash as well. Consider using a long training line or retractable lead while you work on that recall. An untrained dog should never be allowed off lead.