I grew up with (a) Dr. Pepper with a ".", (b) English teachers likely to hand out a clout upside the head for such abuse of punctuation, and (c), a father who was a surgeon, thus "Dr.", although he belonged to the cadre which held that the M.D. suffix was far more important than the Dr. prefix (since it was employed by countless hordes of yahoos and all too many scalawags pastoring Southren Baptist churches).