One of my favorite bosses (and mentors) provided to me MUCH loving guidance as he and I were trying to polish up my leadership skills over the years. (I am eternally thankful for his patient and loving support -- still).
When I would get "on fire" about some particular issue, or when we would be dealing with one of those frequent and inevitable "messes" that come through the leader's door on a daily basis, he would remind me consistently to gauge the significance of the issue before reacting.
More specifically, my mentor's consistent coaching (and modeling) was along these lines:
What is the eternal significance of this current "emergency"?