Dear Ms. Plume,
     I went to visit a friend of mine. I was sitting on her porch when another visitor came. Her two dogs were on the porch with me. My friend (who is now an ex-friend) introduced the dogs first and then as an afterthought she said, "Oh, that's Mary."

While I don't need to ask whether the introduction did or didn't follow the line of etiquette, my question is, when is it appropriate for one to answer without regard to etiquette or civility?
     Would the phase, "Excuse me, you dog!?" have been inappropriate?
     When are we allowed to cross the line of decorum into downright viciousness? My mother is the comeback queen of queens. She is able to cut to the quick with such style and grace, one is pulling the knife out before they know what has happened. I, on the other hand, am always shocked by ugliness so I come up with answers a day later.
     It loses it’s impact to call someone a week later and say something stunningly catty.
     What to do? What to do?

Dear Mary,
     If your so-called friend was rude enough to introduce her dogs before you, then the response, “Excuse me, you dog!” would have been quite appropriate. However, she might have thought you were addressing her dears directly and with deference. Perhaps standing up to your full height, so that you might actually look down upon her, and saying to the visitor,  “It is lovely to meet you, enjoy your afternoon with all the dogs, good day,” might have worked equally well. When people introduce their dogs before their friends, it is indicative of their relationship with both. It is obvious that this woman doesn't have any real non-canine friends and therefore you didn't lose a friend – she was just a woman who went to the dogs.
     One should never answer without regard to civility or etiquette – that is what keeps you above the level of that woman and her dogs. If you don't think quickly on your verbal feet, the day-after witty response can still be effective. You could have sent her a package of dog “bacon/beggin” strips with the following note: “Thank you for the interesting visit yesterday; I thought the three of you might enjoy these for breakfast.”

I empathize with Mary, as I also have a former friend who would carry on simultaneous telephone conversations with me and her two cats. They sounded like this:
Cat Lady: “When we go to Savannah next week I would really like to see poopoo, did you eatums all your breakfast and make poopoo?”
LAP: “Excuse me? I haven't had breakfast yet. Wait, are you talking to the cat??”
Cat Lady: “Angel Baby has an upset tumtum and I had to feed her oatmeal this morning!”
LAP: Thank you for sharing! Now let's get back to the Savannah trip – shall we see that new exhibit at the Jepson?”
Cat Lady: “That sounds great, I'd love to see the hairball!”
LAP: “Hairball? I think it's a hand blown glass exhibit – did they actually incorporate hair into the orbs?”
Cat Lady: “Hairball! (Tone of voice indicates I'm an idiot.) Pookie just threw up a hairball! I have to go clean it up, bye!”
LAP: To myself and the dial tone, “That's right. Good-bye and I'll be going to Savannah alone!”

     I have a dog who likes to greet guests at eye level. This could be entertaining if he was a small, cute,  trained poodle who could execute stunning circus leaps. Unfortunately he is 5'9” standing; needless to say this is a tad imposing to some people. I can understand that if he greeted you in that manner before you were barely able to get out of your car, that I might, just might, have to introduce you to him first by way of shouting his name in exasperation. As for my FF, no point in calling her back with staircase wit (Urban Dictionary definition: “Thinking of the right answer too late; the perfect, usually piercing, riposte that you conceive only when replaying a verbal exchange later in your head.”) because she was just plain catty anyway.
Mary, I have searched and searched through various editions of Emily Post's Etiquette, The Blue Book of Social Usage. I have researched introductions:  To the President, To a Reigning Sovereign, To a Cardinal, To Distinguished Persons, etc. but nowhere do I find a proper introduction to a dog.