So say the teacher you're working with asks you to come up with an activity to fill up the class time for a lesson later in the week.
You spend the day coming up with the idea, gathering the materials, writing, cutting, pasting, rubber-band'izing [it's a word - pipe down you rabble] and generally making it happen.
The next day the teacher says "You know, I forgot that next week is a big, important test so instead we'll spend that class period on a review sheet."
This might cause a lesser man to feel frustrated. Even daydream about such things as smacking said teacher around a little bit.
I, on the other hand, am a Zen master.
My mind is a still pool of clear water. Unperturbed by the ebbs and flows of life. Rolling with the punches. Being water. Relaxed into life.
Also, I've started drinking at work.*
So that helps.
[As far as you know, anyways...]