As a lifelong dog owner I get so, so frustrated when I see other dog owners telling people who are obviously afraid "Oh no, Scruffy is really friendly"!
I'm not fond of spiders, over the years I can cope with them but if there's one in the room one of us has to leave! Usually spider, in a glass with a bit of cardboard - if he ain't paying rent he ain't staying! Imagine a spider the size of a dog, running in all directions, you're unable to guess which direction it's going to head for next, and tell me "Oh no, Spidey is really friendly"! Then I think you could get some appreciation for the fear people have about dogs.