An interesting experience from the other day, with a lesson to be learned:

I was nearing a project deadline at work. I checked in my changes and when I did a production build, found that my coworker had checked in some code without fully testing it, and it broke the build.
I wrote him an email asking him to fix his code. I was tempted to mention how it was holding me up from deploying an important change and otherwise berate him for his laziness.. but thought better of it and changed the tone to something a little more pleasant. It turns out part of my change didn’t build either.. I had just missed it because my errors were farther down the log than his.

Every time I’ve resisted my first inclination to be a little angry, harsh, or even just put-off, and switch to something nicer, I’ve always been grateful afterward. As with President Lincoln’s never-sent letter to General Meade, the trick is just to resist that initial impulse, or even better, change the impulse so it never comes.