I'm too shy to ask people to pet their dogs
What makes you feel embarrassed about asking people to pet their dogs?
I'm afraid to be looked down upon
Feeling shy is ok, but assuming that other people are judging you for wanting to pet their dogs is not always true. It is really good to ask people before you touch a strange animal they might bite you.
If you are wrong I'll leave it
I would feel quite the opposite of judging you, really great if you asked to pet my dog before trying to touch her. I know my pet is scared of strangers and might bite you, so avoiding a dangerous situation is something everyone would approve of.