Announcing your plan gets you applause early, and early applause makes the work feel optional.

Telling people what you intend to do hands you a version of the reward before any of the work starts. The nods and the encouragement feel a great deal like accomplishment, and your mind, having already collected something, quietly loses urgency about earning it. The plan then has to compete with the applause it already received.

Keep the next one to yourself until there is something finished to show, or tell one person whose interest is in the result. If you feel a strong pull to announce that you are starting, treat that as the cue to begin instead.