I have to say, I’ve seen a lot of dogs that were presented as service dogs. And my best guess is that some of them were just “emotional support” and not actually service dogs. But every one that I’ve seen has been quiet and well behaved. My mom (who is afraid of dogs) freaked out when we had to walk by an enormous dog sitting in an airplane bulkhead. But the dog barely looked at us as we walked past it, and sat quietly in its assigned spot for the entire flight. I dunno if it was an official service animal, but it was certainly well-trained.
And that’s been my experience overall. Dog in a restaurant? It stays under its owners chair. I guess three of the service dogs I have seen frequently were obviously helping a blind person on my commuter train. (One of those wasn’t all that well-trained, but its owner told me he was still training it. – I had offered to help, since the dog wasn’t, And he turned me down, because the dog needed to learn to do its job, even if that meant he missed his train.)
So I guess I don’t “get” the annoyance with random service animals.