I would love everyone to have completely happy go lucky dogs who wanted to meet everyone nicely. Unfortunately we don't live in a perfect world and many dogs and humans alike have struggles.
Some things that we can do to help everyone out including dogs with and without struggles are:
Asking before allowing dogs to greet.
But your dog is friendly, whats the problem? A lot of the time it doesn't matter how friendly your dog is, its how the other dog feels. Maybe they fear the approach, maybe they were charged at previously, maybe they're shy. Maybe its not the dog, maybe the human needs space, managing kids, other dogs, just doesn't feel up to it.
The point is its not about you or your friendly beautiful dog, and we can avoid conflict by simply asking before we do.
Recall
I think dogs runnings and exploring their environment is amazing. Its so relaxing for the dog and the human. We can make it relaxing for everyone if we make sure we have a solid recall. I like to work on a regular recall, a check in and an emergency recall. I also use long lines (see my previous posts). By having these options I know I can help keep my dog safe and those around me safe. Maybe a reactive dog, an unsuspecting child or adult, wildlife etc. I can clip Vader up until I can confirm if the person is happy with him off lead or keep him on until another spot comes up for freedom.
Check out STAS for creating a great recall!
Off Lead Parks.
This is similar to the above. Ask if the dog in the park would like to meet yours, if not agree on a finishing up time. This will make the swapping over much less stressful.
If your dog is off lead at a designated off lead beach, you still need to have a solid recall. Dogs who don't love being run at are just as welcome at the beach as the dog who loves all dogs. Much like I don't allow my kids to go and steal everyones fish and chips, I don't allow my dog to go and harass everyone. Sometimes that via a long line, sometimes thats on a reliable recall.
These little things are so powerful. The reactive dog owner or the quiet human will feel more confident knowing they don't have to necessarily interact. Once they feel confident they may change their mind, or maybe not.
Kindness is powerful!