Why do we have conflict between service members?

I am in the Army, Im a 92y. I love it! But why do so many bring on conflict between service members? Arent we all fighting the same damn war? I respect every Soldier, Marine, Airmen, and Sailor equally for their service for the U.S of A. Why bicker? Why do we argue about whos better? We are all fighting for the same reason, why cant we respect each other?