Losing my cool

Have you ever learned something from being in an argument with someone? If yes, Why?

My freshman year of college my roommate and I were not compatible in the slightest. I had morning classes so I wanted to get up early and go to bed early, she had afternoon classes so she wanted to stay up late and sleep in etc etc. We got in a few heated arguments over little dumb things but the thing I remember the most was that she couldn't tell me I was wrong if I started with "I feel/think". Ever since then I have tried really hard to avoid pointing fingers and just say what I am perceiving. I have not been perfect at this but living with her for a while really helped me learn how to deal with people in a more productive way.