Every day, hundreds of minor events happen, some of which upset us, even to a small extent.
Marcus Aurelius said about that: "Learn to be indifferent to what makes no difference"
This quote is brilliant, because how often do we allow small events to ruin our days? How often do we forget a thousand compliments with a single negative comment?
Being indifferent could be a talent, a skill that we all need to live a healthy life, away from anger issues and overreaction.
My life has been significantly better once I was able to just let things go, to forgive people even without them apologizing, not giving much attention to things that don't really matter.
I'm also sure that anytime you'll be successful in doing so, your life will be much better, more enjoyable as well!