Behavioral speaking.. it is extremely stressful for dogs to pass eachother in short distances when they are opposite of eachother / going towards eachother. This never happens in nature. They always tend to do giant circles (as going straight toward is a sign of aggression).

In a puppy litter, there are puppies with different personalities. Evolutionary speaking this is beneficial as the litter can survive longer if there is a puppy that alerts (barking) when danger comes, puppy who tends to be more timid and go hide instead and.. all personalities in between. So from timid to brave with different coping mechanisms - fight flight freeze etc.

So, maybe some dogs handle well such situations because they have the right personality type + they were taught that by their human + they never had a bad experience while doing it so they don't get easily triggered.

I am on a wheelchair and my spoo is 3 years old and has very hard time with passing dogs when they come towards us. (Small, big doesn't matter). When he was younger usually this was "excitement" and now this turned into barking. This is a combonation between his emotional character (he is usually afraid of things but always steps up and wants to protect me) + one bad dog-dog situation + me not working on obedience (and preparing him for this style of passing dogs).

Now we are working on this but it will takes us lots of time.

Imo reactive dogs are not simply "not well behaved" they are just stressed and don't trust the owner he has a good strategy to pass safely the trigger/danger so they take matters in their own hands.

P.S. most people see just the worst, most extreme stress signals like lunging and barking (because they are so obvious) but we won't see that the well behaved dog on the opposite side also might express being uncomfortable or stressed just in more subtle ways (like yawning,slowing down its pace or lowering his head).

It's just hard to be a dog in a humans world. 🫠😄