Going Postal

So lately every afternoon without fail, there is a loud banging on my door by a lovely Post person. As I open the door, I'm anticipating the dialogue, mood, demeanor. Standing in front of me...it's always somewhat the same: male/female in all the postal gear, one ipod ear phone out, holding my mail, kind of out of breath, kinda sweaty "WE WILL NOT DELIVER YOUR MAIL WHEN THE DOG IS OUTSIDE.... SO HERE!". the mail is shoved into my abdomen.
I nod, with a smile and a sarcastic tone say "okay, thank you".
Secretly, I'm pissed.

Let me explain

My Dog is outside. My Bassett Hound/Beagle mix dog is lounging in the front yard. He's so threatening...with his drool and laziness and droopy eyes. Yes he will cut you, rip your head off...he's force to be reckoned with. Seriously?
Secondly, we never have the same postman/woman/person. It's like we are the red headed step child of mail routes...no one wants to deliver in our ghetto Millcreek neighborhood. It's a different person everyday. In fact, when we first moved into this neighborhood 6 years ago we had an awesome post dude...he was a dude. Long hair, tan (kind of my type ;)). He would bring Roscoe treats, pet him and deliver our mail everyday and fortunately avoided any altercation with my easily irritable dog! But these days, I don't know what it is, I've never seen the same person twice deliver our mail. So everyday they knock on the door and think they're telling me something new. I want to be like, "yeah dipshit, the person that delivered the mail yesterday explained your hang up and the person that delivered it the day before that and the day before that...but I'm afraid I'll get myself so worked up I'll papercut their face with my overdue bills.
Thirdly, because of our random bag of players; the mail never gets delivered at the same time everyday. So even if I wanted to make sure my dog was in the house I wouldn't know what time to bring him in. It's anywhere from 1p-6p daily...yeah...so that's cool.
Basically, I don't want to call up the post office and bitch at them and I don't want to be rude to the next person as it may be they're first day of work. I'm not quite sure how to remedy the situation other than right now it's so hot out Roscoe rarely wants to be out there so he just goes out, does his business (maybe kills one human) and then comes back in to relax in air conditioning.
The bigger question here is, why are people still sending stuff regular snail mail?