I love these Rottie pics! The hats definitely help make them look more friendly. Another thing that scares people are prong collars. They see that collar and think the dog needs it because it is aggressive, etc.
I am very cautious approaching all dogs because I know the little ones can be mean too. Our 15 lb lhasapoo is a sweet dog but she is leery of strangers and doesn't like dogs bigger than her (she has been attacked a few times). Our 30 lb mini golden doodle likes everyone. She thinks humans are there for her enjoyment. Unfortunately, I have noticed that some of our little dog's aloofness is rubbing off on her.