In all thy ways acknowledge him, and he shall direct thy paths. We need to trust the Lord. That's a given, a basic, and goes without saying. Nevertheless, the Lord said it so it must be important for us. We need to be confident in the Lord placing all of lives in His hands.
People trust their own intellect, their possessions, their position, and their authority.
Sometimes this is the result of ignorance. They do it because they don't know God. They don't understand God. They don't know that He is able for whatever reason. Maybe they're not saved.