I don't like big dogs, especially if they're energetic. I don't really know why. I'm not exactly scared, but I kind of am because I don't want to go anywhere near them, and if they come near me I try to hide. My boyfriend has a doberman/greyhound mix who's about 65 pounds, and I never liked him much and still don't, but I can tolerate him. I kind of have to since we live together! We used to take him to the dog park together and I would hide behind my boyfriend when other big dogs were playing around. He even works at a kennel and would take me through to see the doggies on his breaks, and I would run past the cages with big dogs in them because even just their barks kinda scared me. I've always had dogs... never more than 20 pounds, though! And that's only because they're fat. Maybe it's just not being used to big dogs.