[header] How to be nice to someone you hate [title] Maintain positive posture and body language. [step] One way to send positive signals to someone you hate is to maintain positive posture and body language. Holding positive body language will send non-verbal signals to the other person that you actually don't hate them. 
At the same time, if you're not aware of your body language, you just might send negative signals to someone you hate. [substeps] Smile, but don't smile in a weird way.