Tucker loves dogs, stops walking and lies down if I'm not letting him go say hi, listens very well to them, he likes to play, etc. Yesterday we went on our walk and he was particularly spazzy, trying to do zoomies on the leash, play bowing for no reason. Shortly after we started off we saw someone walking a big fat Golden (with his hair shaved short, people shouldn't do that), the Golden dragged the owner over and Tucker started play bowing and wiggling. The Golden ignored him and came to me and Tucker started sniffing him. I heard Tucker growl and then he started barking his head off. So I dragged him away and apologized. It was strange because he never went stiff and he didn't lunge or anything, he growled (while still wiggling) and started barking. Tucker has done this once before to a different dog that he was meeting for the first time (though his reaction then was more severe, I couldn't get him to stop barking for several minutes). But he's met this dog before, though it was a while ago, and he was fine with him then. He usually adores other dogs so I was really shocked. Tucker wanted to go back to the other dog, he wasn't behaving fearfully at all, but he kept barking. I waited until he was quiet and then I played LAT as we moved on. We didn't encounter any more dogs on the walk. When we got back from the walk Tucker was paranoid for the rest of the day, like he gets if we have strangers over, he always barks at the littlest things for a day or two. So he kept going off on little noises and seemed anxious. He couldn't settle and was getting into everything, chasing the cats, being a real pain. Later that night we were out in the yard and someone walked by on the other side of the street with a dog. Normally Tucker cries if he sees another dog and will try to belly crawl over to them. But he just went nutso anxious panting and then barking his head off. I felt bad because I know that dog is DA so we started him going too. So I dragged him inside and waited for him to calm down to let him off his leash. Does anyone have any ideas why he might be behaving like this? I really couldn't tell if it was aggression or not, but he never barks when he plays with dogs or people, only when he's frustrated or trying to scare away strangers. He had seen a dog on his walk the day before and was fantastic, though it was a dog he knows really well (his best friend Spike). I'm just concerned, he already tries to eat strangers I really hope he doesn't start hating dogs too.