I don’t like large dogs.
I used to have a bad phobia of them and would get sort of upset when dog people would just let their large dog jump at me. I think it’s part me finding them too big and part that growing up my neighbor had a husky who used to run at and try to bite the small dogs in the neighborhood. And she almost attacked a kid who was walking a dog.
My older brother also had this phobia. My mom says as a young child, he would freak out if he saw a large dog. My younger siblings also had a dog phobia but it was for all dogs, big or small. They used to live in a country where dogs were not nice and should be avoided, so seeing that Americans keep them as pets was a bit jarring to them.