I had to put up with quite a bit of abuse not long ago from a couple of men over this issue.
The first one when I was playing with my dog off lead on a playing field beside a road.
We were in the middle of the field when from, what felt like out of nowhere, this large mastiff type dog shot towards us and started leaping round my 6.5kilo dog.
I called to the owner to call his dog off, which he tried to do, but it was a young dog and was having none of it. It just continued to bounce around while my poor dog was screaming in terror.
Owner standing still, calling his dog from a distance, dog enjoying himself completely ignoring him. Dog eventually goes towards owner at which point I tell him that if he can't control his dog it needs to be on a lead.
After I told him he was being ridiculous when he said my dog went for his dog, which she didn't, he told me to 'shut my fucking mouth up'.
Had a similar thing, oddly enough the next day, in a different park.
Another large dog, retriever this time, ran at me and started leaping on me rather than my dog.
Yet another man who couldn't call his dog back, and had to chase it round me until he eventually managed to grab its collar.
He wasn't quite so rude, just called me a 'miserable old cow' because apparently, he thought that, having a dog, I 'would be used to dogs'.
I appreciate that dogs have their own minds and can't always be relied on 'to do the right thing' but some people just don't get the idea that dogs need training.