I'll tell you the most important lesson I've learned in 18 years of marriage: Take a deep breath and make a heartfelt apology. It really works wonders on anger and irritation and diffuses tension like nobody's business. Believe me, you cannot make an argument that works so well as an apology. This does not make you a doormat. It makes you a peacemaker.
"Blessed are the peacemakers; for they shall be called the children of God." Matthew 5:9
Funny, this advice works for siblings that have had a "knock-down-drag-out", as well as for married folks.