Is it necessary to have a dialect ?

When you are having a mother tongue or a national language or a language in which you are comfortable at, is it necessary to have a dialect? I don't understand why people try so hard to become like someone else, when they can be the best when they are like their own self. People, just to prove that they belong to the same brotherhood, start speaking the same language rather dialect, but they don't realize that they have been loosing the originality in them as soon as they try hard to become like the others. Moreover if you wish to follow someone you can do that, even you can get inspired by someone but it is not at all necessary to always form a trade mark for a profession or a course. For instance, engineering graduates in West Bengal use such a language which easily indicates that they are from engineering back-ground. This is not at-all against the engineers of West Bengal or any other state or country, rather it has got nothing to do with engineers or doctors but it is against this fashion, this trend.