There does however, seem to be an epidemic of manner-less mini's which has created a condition called "small dog syndrome". Because little dogs are so adorable, there can be a tendency to allow certain behaviors to exist whereas the same behavior in a large dog would be seen as threatening or undesirable.
A small dog may not have a big bite, but bites hurt no matter what size the jaw is and, an overture of aggression will not be viewed as "adorable" in the animal world. Typically, aggression is matched or escalated on and, in the event of small breed antagonizing a large breed dog, odds are on the large breed dog to achieve dominance. Dog skirmishes or fights are not "cute" or "adorable", they are hideous and scary and not many pet parents out there are equipped to break up a dog fight once it erupts "out of nowhere".
Allowing an animal to dictate its own state of affairs is not an ideal situation and can lead to bites, fights, re-homing and, in extreme situations, euthanasia if the animal is labelled as out of control and a risk. All of these things are preventable through training and correction. Regardless of size, all dogs should be provided the basics of training and be permitted the opportunity to live a calm and happy life. If you need help with training or behaviour modification, ask around for advice or sign up for some training.