I was walking Cohen down the street yesterday and saw her two nemeses at the corner a block ahead of us. These two dogs are normal, relatively inoffensive charcoal coloured standard poodles, and I don't think either of them have ever done anything terrible to Cohen -- they've just become the object of her ire due to them being two big black fluffy dogs that look vaguely like the big black fluffy dog who attacked her at the park when she was 4 months old. My dog holds grudges. Pointless ones.
So anyways, I had seen these two dogs up ahead, but they were too far ahead for Cohen to notice. So I slowed my pace to make sure they stayed far ahead of us as we made our way to the park. It surprised me that when we got within about 10 meters of the corner Cohen started to have a reactive episode and was particularly difficult to calm down. She'd apparently picked up their scent and found it offensive enough to kick up a fuss.
This pretty much ended up poisoning the rest of the walk. Cohen was on alert and stressed. Since I was unable to properly predict and preempt her reaction all those fun little stress hormones were making their way through her body and generally making her a pain in the butt.
It caught me off guard when Cohen reacted solely because of a scent. It left me a bit despondent when I realized that I could not sense the offending stimulus. How can I possibly preempt her reactivity when I was ignorant to what (or where) the problem is? We managed to fumble through it, and I've learned to give offending dogs an even wider berth than I do already. It was a good example of the importance of being able to correctly identify your dog's triggers when trying to manage and cure reactivity.
Dogs don't react at nothing, despite it sometimes feeling like they do. Clearly they're 100% capable of reacting to stimuli undetectable to us silly humans.