Oh, it irritates me to no end when people do the unspoken greeting thing, because usually they're acting as though they're trying to gather their dog, but, oh, what can they really do? The puppies want to say HI! On the sidewalk, I gather up my dogs and for most people that's enough, although I've still had some approach directly (without asking) even then. The funny thing is that when people do ask and I politely decline, "No thanks, sorry!" they glare at me. So why did you even ask? Pet stores are the worst. Dogs just appear around the end of the aisle on flexi-leashes with no owner in sight. I usually say loudly, "Oh excuse you, where's your owner? Not paying much attention huh?" and then I shoo them away dramatically.