If someone's gestures and movements line up with what they're saying, they can be used to emphasize a tone or emotion. Sometimes gestures can override the words themselves if they don't line up, though. If your gestures don't match your words, then people will pick up on this. For example, if you're complimenting someone or saying something nice, but you're shuffling your feet, avoiding eye contact, and sticking your hands in your pocket, the person may think you're lying or being disingenuous, even if you really mean what you're saying!