One of the best pieces of advice I've ever received applies to both personal and professional situations:
Write immediately, react later.
The takeaway is quite simple, don't let rising emotions guide your reaction. Knee-jerk responses often inflame situations and lead to bad outcomes.
Writing things out provides a great opportunity for reflection. Use that reflection to inform your reaction...and the space between the two helps to settle any emotional influence to your reaction.
Using this approach has helped me to avoid major issues and almost always leads to more constructive, reasonable solutions to any situation. It's not fool proof—I've got the scars to prove that—but it's a reasonable approach to a lot of situations.