The worst of them are both of the latter. Either know less/pretend to know more (or worse yet, both), AND sadistic fucks.
And there are the ones who are really opinionated, and worse, arrogant and up their own dick-eye about it, they really suck ass. Especially the types who INSIST on virtually demanding 'this is how it is, it's how it works and this is so, because I say it is' and who'll continue yammering dogma into your face despite being presented with peer-reviewed, validated clinical evidential data finding their claim incontrovertibly false, or another 'how' is the case. The ones that don't care how much research has been done, because they've been doing their job for XXXXX years and that's that so screw off, I do not care what medical science knows, because I know better than all those other clinicians and research teams, and no, I am NOT wrong, I can't be wrong, if I was wrong, how could I be telling you I am right?' and other such bollocks.
I've met a few really, REALLY shitty doctors in my time, a few even that I really wanted to smack in the mouth right then and there.