I don't think it possible to answer for a person in particular. Being a policeman might be the dreamjob for you, while for someone else it might be a nightmare. It depends of the person, a person should always choose a job he loves.

Each profession is useful for society.

A president of a country)))).
This one is very important, respected and well-paid as well.

I'd say teacher, second to that farmer. Farming, invented approximately in 7000 b.C was the reason for the mankind to exit the paleolithic era and enter the neolithic era. I think without teachers and farmers this whole earth would be full of aggressive, hungry, human-like animals.

every profession play a part in over society for smooth running of the social envirenment,and every professional think that his/her profession is the best profession and the person who is not a professional must have a wish in his heart would that i be a .................. and that profession is the best one for that person

It all depends on the person. The best answer depends on the situation. This is a matter of case-to-case basis.

I think being a professor in a college may be the best career, teaching student , sharing ideas with them, explaining, arguing , contradicting ...really enjoyable and pleasurable. the advantages of that job occur when you are debating with someone then u may found urself able and capable to face facts, to put smth to the vote, to find common ground, to invite comments and reach a convincible arguments .. I suppose that all these stuff are useful in our daily life.