Positive body language can include smiling, waving, and maintaining eye contact, while negative language can include frowning, crossing your arms, moving around and fidgeting, and looking away from the speaker. The difference is that positive body language can improve the mood of a conversation because both people will feel like the other is appreciating what they're saying, whereas negative body language can promote the idea that one person (or maybe both) don't want to listen to the other.
