Adiaphora is a Greek term found in Paul's writing meaning things of indifference. It is an interesting concept in Christianity that there are things central to faith and things not central.
The distinction between what is central and not central is always difficult. The importance of the concept is always to consider when we dialogue with other Christians who have different beliefs that some of the beliefs may exist in the non central part of Christianity.
There are always things worth fighting about and there are things not worth fighting about. Liberal theology puts all things in the "not worth fighting about" category.
Actually Paul's use of the term implies there are things worth fighting about, since he is stating non central elements are not worth fighting about.
Paul engaged in a number of theological debates, so there are things worth fighting about in the church, but it is important to remember there are many things worth not fighting about.