 Why's she so late? Am I getting stood up? Why? So you don't know if any of these things are true. Instead you should fill your mind with the most positive interpretations of why they did the thing that annoyed you. Instead of they didn't show up because they don't like me, you could think maybe they had car trouble and they're too busy dealing with that to let me know. Even if that isn't true, coming up with the most generous reason why someone did something that bothered you, helps instill more empathetic thinking towards others in your mind. Not only will this rule help you become more kind of compassionate towards others, but it will also help you be more forgiving of yourself when you have a bad day.