Animals and children can tell what you're about as soon as they look at you.
If dogs can smell stress, anxiety, through your sweat and it smells horrible! That in turn makes them feel bothered and tense, and combative.
Wouldn't anyone if they had super sensitive smell and were forced in close quarters of a figurative moving junkyard?
Voice level and tone matter too. If you're too loud or constantly chattering they're super sensitive ears have to suffer through all of that. Dogs are also very smart and can tell what mood you're in based on your voice tone.
Neon-Skies
Maybe! You never know...