"Be angry and do not sin; do not let the sun go down on your anger."
One of the best verses (and life lessons) my dad taught me. You just feel a bazillion times better when you make amends. Personally, my anger evaporates pretty quickly. Once I get some distance from the hot topic, I usually can see a) the error in my actions b) the error in my judgments/words c)my correctness in my words and actions, but decide that the relationship with that person is way more important than me being right. And I take immediate steps to apologize or just clear the air as soon as possible.
This happened tonight with my roomies. I can't tell you how much I love them and how grateful I am that I followed the advice with this situation (although it was extremely minor...they didn't even know I was angry). I just feel so much better and they just feel loved. Yay.