Rocky and Bella do the same thing, occasionally they'll have good days where they'll be nice to other dogs they see on their walk, but usually they act like they need to kill all the other dogs in the neighborhood! Also, it's only when their with me, when my fiance walks them their perfect little angels
I tried the spray bottle, but with Rocky he just gets more PO'd and starts barking at the spray bottle. Now I'm working on just getting them to focus on me when they see another dog, and if they do they get a treat, but when they see other dogs usually they tune everything else out.