Our Little Socialite OR Are there cultural differences between dogs?

As I mentioned earlier, Ashby is a Formosan Mountain Dog mix.
We didn't do much research before we got her, but the foster Mom told us that they are very hardy and healthy dogs, and can easily reach 15+ years.

According to Wikipedia, "The Formosan is a high energy, loyal, affectionate, and intelligent breed that learns very quickly. In unfamiliar situations, they tend to be wary of strangers and sounds, and they can become fear-aggressive. In new situations where the dog is fear-aggressive, it can take a few days before the dog will calm down.

If comfortable and well-trained, the Formosan will be friendly to people and other animals, though they tend to be a bit aloof or suspicious of strangers once they have bonded with their owner. Once bonded, they are extremely loyal and affectionate to their owners."

Supposedly, they also make great guard dogs. But not our Ashby. Our observation is that she is great with people - she is very submissive, but will always approach people, lick them, and generally be the greatest dog out there. 
With other dogs, however, she will at best sniff them, but is extremely cautious. And as soon as the other dogs play a little more roughly or worse, BARK, she is off in a different direction. She is really shy.
Here is about the best we get from her when there are other dogs around, note the hair still standing up a bit, not quite at ease:

She will also not play when the other dogs are around. But as soon as they are gone, she will go back to play ball, or run alongside me. Well, I guess at least I'm getting my exercise that way.

This made me think of our Asia vacation this summer: There were many, many dogs there, and they looked similar to Ashby. Some had owners, some were running around as strays. But I never saw any aggression in any of them. I didn't really see play either - the dogs just seemed to live alongside each other. I only once saw a dog walked on a leash.
Ashby spent the first few weeks at the foster Mom with many other dogs, so she should be very comfortable around other dogs. However, maybe not the dogs we have here. 
So this made me think: Is there a "cultural" difference between dogs? Does she have a hard time interpreting the rambunctious and sometimes borderline aggressive play of other dogs? And will this change, or is it just her temperament?