For The Love of Language Part Deux

Please do not glaze over.
Please don't glaze over. (You'll get this reference in a minute, trust me).
The lesson today is about helping verbs. More specifically, it's about the correct use of the helping verbs do, does, and did, especially in a negative construction where we may use "not" with the helping verb in the form of a contraction.
Do I bore you? I bet I don't.
Did she work today? She did not.
Or, no, she didn't. That is, she did not work today.
First, what led me to this, dear reader? I drive down highway 35 every day as I head to the University of Oklahoma.
And each day, I see a sign, and each day, it bothers me more and more.
The sign is for a barbeque joint run by a man named JR who decides to use this ad slogan, "It don't get no better than this."
It doesn't? I bet it does. Even though I'm in the South, "Nay, Nay, I say."
Let's break that down and see why that is an absolute abuse of the English language.
"It do not get no better than this."
First, the subject in the sentence is "it," so right off the bat we do not have subject-helping verb agreement.
Nay, nay, I say.
The appropriate helping verb is "does," and then the addition of our negative, "not."
Therefore, "It does not get no better than this."
BUT, wait. We have another glaring problem with this sentence. Which of these words doesn't belong? "IT DOES NOT GET NO BETTER THAN THIS."
JR, you're abusing the English language horribly and putting it on billboards so that Jane and Joe Q. Public thinks that is correct.
Shame on you!
Take away the double negative. "It doesn't not get better than this."
We can add a simple qualifier as well, if we want to provide more emphasis to the meaning of the sentence. "It doesn't get any better than this."
There. I feel much better now.