There are certain things I have definite opinions on. I don't generally cling to a particular perspective "just because"; I have reasons for my beliefs. As such I am confidently able to defend them. But I need to always keep in mind which belief is foundational, which is important as a load-bearing wall, which is a curtain wall, and which is simply paint that can be changed fairly easily. Foundational beliefs are worth dying for. Load-bearing beliefs are worth discussing and defending with broader audiences, and possibly dying for, although I might not make them central to a relationship. I can recognize that someone can be an excellent Christian, built on the same foundation, even with different central beliefs, and I can choose whether it's the right relationship or the right time/place to discuss those differences or not. Curtain walls are those beliefs I am pretty confident about for my own life but I don't think everyone will have the same number or arrangement of rooms. If you press me I am ready with my explanation, ready to convince you that you might consider rearranging your house in the same style, but I'm not likely to bring up the subject as I recognize that not every Christian is called to the same lifestyle. Paint on the walls are the opinions I am ready to change if the evidence is convincing enough.
Why such a lengthy explanation of the differences? If we think all our beliefs are equal to each other, we will squabble over every issue or will lose our faith altogether in the effort to get along with one another. Knowing the comparative importance helps us discern which ones are a matter of choice or depend on our specific call in the Lord and which we hold onto more tightly. We come to realize that some are important yet other Christians who hold different beliefs are still very clearly following the Savior--and so we can set them aside, as important as they are, for the times that we are together rather than fighting and disparaging one another's beliefs in an effort to convince one another.