I have split this from the ' what is it that bugs you' thread
Coaster see this thread
for a bit of background.
I had got to the stage where she was off lead and socialising well with other dogs but she was pinned down a couple of times and got distressed and one day she went for a dog who she had always been wary of and who had been very boisterous with her. She had to be on the lead after that which does not help the anxiety. Mostly she is just vocal when worried but she can be aggressive if very frightened.
She is okay with family and friends dogs but I am able to plan meetings. We usually meet on route and keep moving. The other owner has a treat assuming their dog isn't treat possessive. After one positive meeting, there are no further problems. Once she knows a dog, she will be fine but TBH largely indifferent to it. I am also fine with meetings if I can have a discourse with the owner before. If they understand that she can be reactive and that I may just make a sharp retreat if her body language changes. I try to keep the lead loose when other dogs approach. If she starts to pull, I move away and keep her away as she is already anxious. As she doesn't seem to gain much from being with other dogs, I am happy to keep working at good manners on passing. I don't avoid other dogs but I don't go out of my way to be with them. Her behaviour is consistent whoever is walking her. It is difficult to know what may have led to this as she is a rescue.
ETA I always treat and praise positive encounters.