ANSWER:

If they order you to do something they believe that it is best for you and there is no harm on you because of it, it is advisable to obey them. 

Sheikh, I respect my parents, I am kind to them, I don’t raise my voice to them as instructed in Islam. But my question is, is it also compulsory to obey everything they say? Like things which are not fard like they say to shorten the hair but what if I don’t like short hair and don’t cut them short?