Knowing one's place

Having been in policing for over 20 years now there is one thing that keeps bugging me. Never have I seen it in any other occupation, but policing. I have been through a police training academy, many schools over the years and I hold an Associates Degree in Criminal Justice. I have been certified as an instructor, special investigator and I have a Master Peace Officer License. With all this you would think I know just a little about working a crime or just a little about the law. However, it never fails that some citizen tells me how to do my job. I have had someone even tell me that I did not know what I was doing. I wonder, do these people hire a plumber and stand over him telling he is not doing his job right. Do they go through the line at HEB and tell the bag boy that, "No, milk and bread do not go in the same bag!"

So where do they get off telling me how to do my job? What is it in a person that they think they have to tell a policeman how and what to do while he is doing it? Come on people, I did not go through all that training just so you could tell me how you think I am doing wrong! Think you can do it, then go get your peace officer licence. No, wait, then you will have people telling you what you are doing wrong.