Think about how you would feel if a stranger ran up to you while you were out walking. Even if the person had a smile on his face you would probably be nervous. You might enjoy meeting new people, but you probably want them to stop a few feet away and introduce themselves properly. However, if you didn’t enjoy meeting new people, going on walks could become torture because you would never know when some stranger would rush up and hug you. You might get defensive and start shouting at people when they were still a block away to make sure they stayed away from you.
So, now imagine your dog. Everywhere I go I see people letting their dogs rush up to other dogs on walks. Often the person is shouting, “He’s friendly, he just LOVES to say hello.” Sometimes the dog on the receiving end is ok with having a strange dog rush into its face, but often what I see is one dog cowering or trying to back up. The greeting may still go ok, at least to our eyes, but not always. I get a lot of calls and emails from people asking why their dog is ok in the dog park, but growls, lunges, or barks at dogs on walks.

This dog sees another dog in the distance and is straining toward the dog. The dog is getting tense and is barking and growling. It wants the other dog to go away.
One person recently told me her dog grabbed another dog by the neck when they were on a walk. The dog is great in the dog park and loves to play. The dog owner was terrified of this new behavior. Prior to the neck grab, the dogs had both rushed toward each other and done a few sniffs, then one dog got scared and the neck grab happened. Another person told me about how her dog was bitten in a pet store, after she allowed her dog to rush up to a dog on leash. It turned out the biter had just been with its new owners for two weeks and this was its first trip into a pet store. It got stuck between a cash register desk and a wall and had no where to go when the other dog rushed up to it.
Somehow we have this romantic notion that our dogs want to meet all the dogs they see on a walk and “be friends.” Sometimes I think we love our own dogs so much, we want everyone to meet them and love them as much as we do.
I don’t allow my dogs to meet other dogs when we are on a walk. When I walk on the Monon (a local popular walking trail) my dogs know we aren’t meeting other dogs, so they just ignore them. If I see someone whose dog is dragging them toward my dog, I stop my dog, stand in front of him and stop the meeting from happening. When the other person tells me how friendly his dog is, I just smile and say that my dogs prefer not to meet other dogs. I don’t care if the stranger suddenly gets the idea my dogs are dangerous. I don’t care if I sound rude. What I care about is that both Batman and Condor have no issues taking walks in public. They don’t get nervous when they see other dogs, nor do they become frantic when they see other dogs in the distance and try to drag me to them. Both Batman and Condor can play with other dogs and both enjoy certain doggy friends, but only when the leashes are off and we are in a safe, large, fenced enclosure.
I see so many people whose dogs have learned to drag them toward any dog they see as the dog has learned that it will meet the other dog and it wants to get to that greeting as soon as possible. Or I see the opposite end of the equation: a dog that is terrified of meeting another dog and starts to cower or back away. Often that dog may lie down and become submissive; leading the owner to think the dog wants to meet the other dog. And then there is the poor dog owner whose dog gave up trying to back away. Instead the dog decided that the best offense was a good defense. That is the dog that becomes reactive and often is then labeled “aggressive.” I get many calls from people who say, “I can’t walk my dog anymore because he is aggressive toward other dogs.” When I get more information, I find the dog is lunging, barking, hackling, sounding ferocious, etc. whenever it sees another dog. In reality, this is probably a dog that just wants the other dog to stay away from him, but the dog has learned on previous walks this isn’t going to happen, so the dog has decided he has to take matters into his own hands.
Remember, when your dog is on a leash, he can’t run away. He may want to run away, but since he can’t he may feel he has to sound scary to make the other dog go away. Sadly, once that dog is lunging, barking, growling, etc. he may be so over stimulated that if the collar or leash breaks, he may go forward and fight rather than running away.
Even if you dog is a social butterfly and loves meeting and greeting all dogs, chances are good that the dog he is meeting may not be having as much fun.
So, leave the doggie interactions for the dog park or your yard where the dogs can be off leash. Just remember how you would feel if strangers started rushing up and hugging you.

These dogs are meeting off leash. While the little dog is a bit nervous about the meeting, he has plenty of room to run away. If he were on a leash, he might feel trapped by the other dog and decide he had to protect himself. Instead after a few seconds, these two dogs moved apart and sniffed other areas of the yard side by side for a few minutes as they both got to know each other better.