My dogs don't like my father so I know it's true. We have a friend who had a hunting dog that if his dog didn't like you neither did he. His dog Nochie didn't like a lot of people and known to bite but he liked us. I figure it's because he knew we love dogs Lol.
I had a poodle a long time ago who loved everybody except for one neighborhood boy. Whenever he came to the house, she would go ballistic. We figured he may have done something to her, but as far as we knew he was never alone with her. Anyway, he grew up to less than an upstanding citizen and came to a tragic end. Either way she knew something just wasn't right. Two of my three current fluffs take their time when new people come over. It seems to take a couple of visits before they fall in love. Only once did Sophie ever really go at someone. It was out of the ordinary and embarassing as it was my daughter's mother in law! She just didn't like her I guess.
I really think that dogs can sense things about a person. When Laurel was a puppy, I took her to a dog training class. There was a retired , very frightened, withdrawn ex K9 German Shepherd. He was sitting behind his owner shaking and frightened. The new owner of this dog was hoping to help him be more social around people, other dogs, and new places.
I was seated next to them, and the dog stood up, and walked over to me. He came close and put his head down almost on my knee.
The lady was really surprised. She said that he never goes to people ever! She said that I must be a good person and that the dog knew that.
I felt happy that she said that, but I felt sad for that dog.
I am very suspicious of people that don't like dogs or if a dog does not like someone. I also think that people with dogs are more compassionate and more outgoing. So if my dog doesn't like you...Well....
Jodi knows who to avoid when family is around eg certain kids who are too loud and rough or try to play with him or hold him if I am not watching (when they know I disapprove). So I keep him close, if Jodi is not already trying to stay close to me. He is not aggressive to others he is just afraid and wants to be with me. But that says a lot. They know what energy to avoid. My cats used to stay in the basement too and come upstairs almost the instant the front door closed behind the guests as they left.