Be mindful of your mood.
Pay attention to how you react to the people and circumstances in your life.
If little things bother you for seemingly no reason, or if you have what feels like justification for being annoyed by small things that occur in your life, know that this is not healthy.
It is highly likely that something else is going on.
You may not be getting enough rest, nutrition, exercise, or even play.
Or you may simply not be addressing some bigger issues in yourself or your life.
Either way, every day occurrences and interactions should not drive you to frustration, annoyance, or anger.
It is not healthy for you or for your relationships, and no one should have to tolerate it.
Do some soul searching and ask yourself what is really going on.
Do your best to address whatever it is one thing at a time, as every change will take time and effort.
When you reach a point where you are content in yourself, your relationships, and your circumstances, you will find that getting upset about small things is the exception not the rule, and that it is a symptom of a bigger problem that needs to be addressed.
Take care of yourself because life is too short to be short-tempered.
Your mood is ultimately your responsibility.