You should respect others' opinions.
David is talking to some friends about basketball and one of them disagrees with him about which team is better.
David wants to make a counterargument to his friend.
David says he understands his friend's points and calmly expresses his thoughts about which team is better.
David yells at his friend and calls him a moron for thinking what he thinks.
David's friend understands, and they are able to have a civil conversation on the topic.
David's friend gets upset and there is awkwardness in their group of friends for the rest of the day.