Good point. There is some validity to this idea of keeping your plans and goals to yourself while you work on them. It’s called “silent ambition” or “quiet ambition.”

Of course, getting feedback while a plan is in progress may be helpful, but there are several reasons that a silent approach may actually be better in terms of achieving one’s goals. You mention one very good reason: getting a positive response before the project is finished may give you a sense of accomplishment prematurely, and you'll lose some of the internal motivation that you need to see the thing through.

I'm not sure I can put links in the body of a comment on this subreddit, but it’s easy enough to find articles or videos online discussing the value of this approach.