It is condescending. It is inexpressibly annoying. It will make you want to masticate broken glass.
It is the emphatic auxiliary verb.
Let me give you a few examples. You will understand immediately.
We will say: "You need to get that report to me by 6 PM." But the disgusting, writhing, repulsive branch manager prefers to phrase himself thus: "Now, you do need to get that report to me by 6 PM, m'kay?"
We, who still have a modicum of natural feeling, who still have souls, who may call ourselves human, might say: "Don't be late again." But he, the centipede, the reptile, the basilisk, is heard to say, contra naturam: "Now, I would advise you not to be late again."
What is the term for this grating, this blood-curdling, this ghastly habitual use of emphatic auxiliary verbs?