Hmmm, interesting question, yolo. Personally, I tend to not use titles like Mr., Mrs., or Ms. unless I'm in a situation in which I feel there's some formality involved that requires it. I tend to not like at all, self-titling, for lack of a better way to describe it. I prefer to judge people on their character and behavior, not on the letters following a comma behind their name. Plus, in today's watered down world of academia, I honestly believe post graduate degrees just don't carry the same prestige that they did as recently as 15 or so years ago, plus or minus.
As for something like a PhD, in my line of work, I've known and worked for most of my career with people who have plenty of letters behind their names. The ones who are big on making you aware of those letters have seemed to be more like pompous a-holes than those who don't care whether or not you know.
I remember one time when I was a young lad, working for a tech startup here in the valley, and we had a rather contentious call with an individual (I don't recall if it was a customer, or a vendor, or what...) and this person felt we were being difficult, and that he was right. So he threw the fact that he had a PhD in our faces, in what I felt was a desperate attempt to give his point of view credence. Well, our head of development, it turns out, had two PhD.s, and he said something to that effect, and then said that both of their post graduate degrees just didn't matter. That made a big impression on the young Fat_Elvis.
As for Dr Dre, that's one doctor who obviously needs a lot of attention! Not because he's a Dr., but because he's in show bidness. In the bidness of show, you need a lot of attention, or you're nothing but a big ol' FAILure.