You shouldn’t be any more impressed by someone simply because they tell you they're a doctor rather than a plumber.
There’s a name for this phenomenon: the halo effect. It occurs when one positive trait, i.e. status related to being a doctor, leads us to assume that the person has many other positive qualities—most dangerously, the assumption that they genuinely care about doing their best in their endeavors.
Doctors are revered, at times very reasonably, for the noble pursuit of saving lives, but if you dig deeper, most of their respect stems less from their actual performance and more from how long they had to study. That’s why it’s very common for doctors to hang their diploma on their office’s walls rather than a track record of the patients they helped.
This is a bold claim but we can all recall hearing--or saying--: "Wow, 7 years of medschool, plus three more for a specialization?” No other profession demands as many years in school, which is partly why doctors appear so noble. In fact, many people rule out medicine entirely because the lengthy education seems too daunting.
But here's the catch: simply enduring years of training doesn't guarantee a doctor cares deeply about each of his patients. The degree to which one performs well is the degree to which one cares about doing his best possible job, independently of the profession. The plumber who meticulously ensures your bathroom renovation is flawless shares something critical with the doctor who stays late checking test results: both are driven by pride in their work, not merely duty to a customer or patient.
You're just as likely to find a caring plumber among a pool of plumbers as you are a caring doctor among a pool of doctors. So why automatically place more esteem on the stranger who introduces himself as a doctor? If anything, you'd rather have to deal with a bad plumber than a bad doctor, precisely because the consequences differ dramatically.
There’s a very easy trick to figure if someone you're talking to actually cares: ask them something—anything—about what they do. It can even be wrong or naive. If their eyes light up as they explain, you're looking at someone who genuinely cares. And that's the only real quality worth admiring.