Does anyone else find it really pretentious when non-medical doctors actually refer to themselves as Dr.? Like, who are you trying to kid; how 'bout we call you schmoctor. That's more like it. If your "D" is not in "M", you're not really a doctor mmmkay. I'm also aware of a few "honorary doctorate" recipients that also refer to themselves as "Dr." 
No, I don't find it pretentious. The term 'Doctor' is an honorific used to convey one's
bona fides to teach and practice a subject/discipline as an expert (from the Latin,
docere, to teach, and
doceo, I teach). In the U.S., physicians are given a
professional doctorate, namely, an M.D., or Doctor of Medicine.
As for pretentiousness, my own, very narrow and very limited, experience has not only encountered some extremely gifted M.D.s/researchers, but also plenty of non-research physicians and diligent medical students who are not,
contra their own self-assessment, what I'd call tippy-top smart (bright, for sure, but in the world intelligence/academic scorekeeping, not brilliant). I'm not trying to be a research snob(
), and this is no knock against run-of-the-mill M.D.s, they have worked very hard for their achievements and contribute meaningfully to the common good, but that's been my observation (for whatever it's worth). And, of course, there are very accomplished physicians that are also medical researchers; for example, in the U.S., an M.D. + Ph.D. with a strong record of obtaining research grants and/or publications in eilte research journals.
