Don't hold grudges with the people close to you, especially over petty, insignificant things. Suck up your pride, apologize whether you're right or wrong. Don't leave angry and don't go to bed angry. Life's too short.
People give too much credit to the idea of fate. While some things are certainly by chance and out of your control, many others come down to choice personal responsibility. If you want to keep people in your life, treat them well.