I'm good at the actual engineering, better than a lot of people around me. But I watch people who can't do half what I do get promoted past me, because they know how to talk themselves up and I never learned to. It stings to be the one who does the real work and gets passed over for the one who sells it.
More people experience this than they realize.
You do the harder work but get passed over by people who are better at selling themselves.
If this sounds familiar, the Library can help you find the bigger picture.