Every leader routinely encounters difficult and frustrating situations. Don't allow these situations to frustrate you. Think of the larger context and the importance of any given matter in relation and comparison to all the other issues you must address in your personal and professional lives.
When faced with a difficult situation, methodically gather information, assess impact, develop an appropriate and proportional response, execute response, and monitor the outcome. Finally, put measures in place to avoid similar situations in the future.
Remember to never exhibit your frustrations publicly. Methodically and calmly tackle the issues presented to you.