At a fairly young age, I thoroughly internalized the adage: it is better to keep your mouth closed and be thought a fool than to open your mouth and prove it.
Mostly, the inclination to keep my thoughts to myself or consider my response before speaking has been useful. But although I have always been comfortable keeping my mouth shut and not worrying about the conclusions people draw from that, I learned that from other sources. The wisdom of keeping your own counsel and thinking before you speak is not really the message I internalized from the folk wisdom.
For some stupid reason, the message I internalized was “better not to admit you don’t know the answer, than ask the question that proves your ignorance.” And that is terrible approach to take to almost anything.
Unlearning a reluctance to ask questions is hard. Breaking a habit of not bouncing ideas off colleagues is also hard. Changing both of those patterns is much easier than treating yourself like you’re still competent, even though you had to ask for help.
Fortunately, most of the time when I have consciously gone against the bad habit of not-asking, I’ve gotten the information I needed to solve the problem. Unfortunately, I haven’t always worked with–or for–people who made asking for necessary information comfortable or productive. That’s the next step, making sure that I make it easy and productive for people to talk to me when they don’t know what to do next on a project, or don’t know the answer to a relevant question, or just think another opinion will clarify the next steps.