When you cannot hear clearly it is easier to guess than to verify what has been said. In this way we end up hearing things that were not actually said. We can imagine and truly believe things we thought we heard.
Sometimes a person can be so desperate for direction that they will baptize their own imagination and call it God.
The true followers of Jesus have learned to distinguish His voice. The voice of Jesus is trusted and gives guidance. A sheep that listens to its own imagination will wander off and get in trouble.
Just because someone claims God told them does not mean God actually did. If you are not sure about what you heard, you can cross reference with the Scriptures, other followers that recognize God’s voice and by asking God to repeat and clarify what you think He said.
Poor listeners get into all kinds of problems guessing at what God might be saying.