Do they do important work? Yes.
Have I ever had good, helpful service from doctors? Yes, and I'm thankful for it.
However, they are also a pretentious, patronising, bullying group of people who think they are more intelligent than everyone else, and are overblown by their self importance.
On a scale of essential professions, they come a long way behind, engineers, farmers, fishermen, hunters, builders, carpenters and many other craft workers, teachers... Only the sick need doctors, and then, only when they are sick. And I'm getting fed up with my doctor's surgery who keep summoning me for tests to check for this, to check for that, as if I haven't more important things to do than sit there and justify their existence. If I feel unwell, I go to the doctor, when I feel fine, I don't. I don't want a bunch worriers hovering over me incase there is something wrong with me. I will live until I die, and that doesn't make a jot of difference to the world in general.
Sorry for the rant, you asked the question.