“He (Moses) went out the next day, and behold two men were quarreling. And he said to the wicked one – Rasha – ‘Why are you hitting your friend?’” (Exodus 2:13) Rashi: Though he had not yet struck him he is referred to as a Rasha – wicked person – just for raising his hand to strike.
Planning to “get someone back” is also an act of Rashanu. If someone hurts us and we spend time scheming to avenge our suffering, the scheming is Rashanu.
“A scheming man causes wickedness – Yarshia.” (Proverbs 12:2) One who spends time thinking how to hurt others is a Rasha. (Vilna Gaon, Commentary to Proverbs) When we spend our time thinking of “I could have said” or “I should have said” and “I should have put him in his place”, we are acting with Resha,
We spend too much time thinking about our anger and hurt and that thinking can lead us down the path of Rashanu.
We can learn to let go of hurt and insult.
Whenever we catch ourselves thinking of how we can hurt someone, we should immediately refocus on how we can help someone else.