I agree with this so much. Whenever someone asks me my plans, I tell them, "I have so many huge plans, but I can't talk about any of them."

The reason why this is bad is because you start getting attached to the outcome. When you tell your plans to someone you are materializing a version of the outcome that may or may not happen - which leads to 2 bad outcomes:

1. You place unnecessary pressure on the idea or plan because whereas before a myriad of outcomes were possible, now only a few are. This prevents the idea or plan from growing naturally.
2. You give yourself unnecessary dopamine - the process of materializing something is a chemically-desirable activity for the brain, which is why people love talking and being heard. The problem is that now you've increased the dopamine threshold for your plan, meaning that when it comes to doing the hard work, you'll be less motivated to follow through.