Why do dogs bark at certain people?

Unless your dog has a pattern of disliking certain things, then I would be careful of that guy. My pit doesnt like tall dark guys that wear bright colors. He wont bark, but he will stop and stare at them until they pass. So im not worried about those people because my dog just has a problem with them.

maybe, maybe not. Some people are just not dog people. And sometimes in a strange enviroment dogs feel the need to protect us from the unknown. Just make sure you keep a phone or another device on you when out and about. Just to be on the safe side.

And your mom is right about the dogs sense of danger.

It could be an experience he's had with someone and something about this person, whether it be the stature or the smell or something else, could remind him of it. I used to have a dog that barked at children, and it was because the paperboy would throw rocks at him, so he expected all kids to do it.

the dogs instinct is to protect his pack.you are part of that pack to him.so I would heed the dogs alert...and just be aware ,or when you can just avoid that person.I think its safe to trust the dogs Instinct in this.