I honestly think this "I want this, this and this" comes down to how we infantalize adults in modern society, and how that comes out in the way that we pay for healthcare (insurance or social programs rather than out of pocket) and in the drug war. About half the time I go to the doctor, I already know what I want (i.e. not for diagnostic reasons) and if I could get it and at least try it out without a prescription, I wouldn't need to waste my time and the doctor's time. Sometimes I don't know what's wrong with me and I actually do want to utilize the doctor's diagnostic skill, but that's not always the case - the same is true when I visit a mechanic, sometimes you already know you need an oil change and a tire rotation or whatever.

Yes, people might make the wrong call about their health sometimes, but that's not the doctor's concern - they're adults, not infants, they've earned the right to make their own mistakes.