It depends on the type of doctors.
General practitioners have been okay for me except sometimes it took them awhile to get it right.
I judge dentists/optometrists/orthodontists and similar doctors based on how much they seem to want to get rich. I have overheard medical students talking about how great it will be to make so much money, and you can see that reflected in doctors as well. If they want to help people, I like them, but many of them seem to be in it for money and prestige and don't really care. They can/often do give poor recommendations that are often motivated by their own desire for cash, and that makes me hate them.
I loathe psychiatrists for the same reason as above.
And I don't think that plastic surgeons, except for reconstructive surgery (i.e. after an accident), should exist. People are spending so much on them nowadays to conform to ridiculous ideals of beauty.