Indeed, specifically breed plays a large role, since it reflects what values are important for the owner. A fighting dog is a clear red flag, even a common German Shepherd will make a person look somewhat more threatening.

A Golden Retriever will on the other hand project friendliness. There are small dog breeds like Yorkshire which are rather aggressive, but in my perception they wouldn't increase the threat perception.

These are of course stereotypes, they won't be true every time, but are IMHO useful as a rule of thumb.