I think this is valuable advice, and it applies not only in this productivity context but in any day to day situation.
I feel worked up, angry, disappointed with those around me in certain situations. Whereas 5 years ago, I might get worked up and complain about all of it to my manager, I’ve learned to recognize my own emotional state. I feel X because of Y reasons.
In 30 minutes after I’ve had a snack or maybe just a glass of water, I’ll feel significantly better and will want to take back anything I say now. Not because I’m wrong or that what someone did or didn’t do is actually right, but because I need to control my emotion and how I respond. There’s a correct way to approach the problem.