Doubt in null and alternative hypothesis testing

Will it really make a difference in final answer whenever we are selecting a statement for null and alternative hypothesis, because I see whatever we are testing the answer depends on correct logical interpretation of the rejection region. So even if we select a wrong null hypothesis, but interpreting correctly corresponding rejection region then also we will get finally the correct answer for alternative hypothesis and vice-versa for null hypothesis. The only rule which will be violated from the rules you have mentioned is the one that "The researcher is always trying to reject the null hypothesis", which in this case he/she might have to accept it if his/her critical value lies in acceptable region.

Do let me know whether I have interpreted hypothesis testing correctly or not.