Walking the Dog

So, in my unemployment, I've taken up doing odd jobs. Currently I find myself as a nanny replacement until the neighbors find a new one. It's a fairly stress free job, I walk the dog at 10-11, and again at 1-2, run errands (dry cleaning, grocery shopping), and pick kids up from school. Now, the dog next door is a pretty relaxed dog, maybe like a schnouzer/poodle or something, I'm not quite sure, but it's pretty mellow. It doesn't chase or bark at other dogs, it doesn't try and dig holes, it doesn't try and escape during walks, etc... I mean, it will go after a squirrel, but only if it's within like 5 yards or so. However, today, when I was walking him, we passed a mail truck (mail car? we passed the postman at any rate), and this dog went as close to berserk I've ever seen it. It struck me, all those times I watched cartoons and the dogs went after the mailmen, I just figured it was a dog-stereotype. Maybe there's some truth to it.