Results of any examinations does not depends on the subjective satisfactions of the examinees but by his perfomance. But if he thinks that injustice has been done to his perfomance he can apply for examination of his answer scriptts.
One point here is that a competative exam is different than the academic exams of schools and colleges. In academic exams if you have done well in the papers you can confidently say that you'll pass. But as you know in comp. exams there are some particular number of seats / posts to be filled and only that no. of candidates are selected. So for eg. if there are 50 candidates to be selected and even if candidate A has done good in the exams, but if there are 50 other candidates who have performed better than A, then it is obvious that A shall not be selected. So even if a candidate knows his merit, he may be not aware of the merit of the other candidates. Of course, there may be cases where there is injustice done.