During pre-historic times, when going to the office was a thing, there used to be a traffic policeman in my commute route. The archetype of a police person is someone who is grim, officious, with a no-nonsense attitude. This policeman was the opposite. He was well-groomed, neatly dressed, fit, had a big smile on his face, and used to greet the passersby. I could not help but think—wow, must be a great policeman. Mind you, I had zero data(that matters) to evaluate his performance; all I saw this person do was manage a trickle of traffic with a smile.
I underwent a routine health check. Once the reports were in, I had a consultation with the doctor. The doctor ran through the report, explained it eloquently, answered my questions patiently—he did all this with a pleasant smile on his face. I could not help but think—wow, must be a great doctor. Mind you, I had zero data(that matters) to evaluate his performance. He did not do any investigative or diagnostic work; all he did was explain the report to me. I could have probably done the same through Google.
It is easy to mistake friendliness and excellent communication skills for being good at the job. Charm can mask inefficiencies and give others the impression of you being great at what you do.
When you evaluate someone, discount the charisma. Do not mistake affability for effectiveness.
The policeman and the doctor might be highly competent at their job.
I am not saying you should be a jerk. Having a pleasant personality will do wonders for your life. If it does not come to you naturally, work on it.