I think its because the weirder the sentence, the more it sticks in your head. The one sentence I haven't forgotten since it first came up on this app is "Bărbatul mănâncă păianjeni?" I can't think of when I would ever NEED to know how to ask if the man eats spiders, but I certainly remember it.
Not as much as they want you to believe it. Of course, there are some aggressive packs, but also they were made by humans, by only catching the nice onces and leave the others on the street, because they are afraid of them. But most of the stay dogs are really very social and smart dogs, most with bad experiences with humans. And cars...
More so than in other places. I was attacked by dogs 3 times within a year when I was living there. And they weren't all strays.