What I will remember is that how you make someone feel can last a long time–good or bad. Everyone likes to share quotes and here is one of my favorites. While I don't know where I heard it, the quote is something like this:
"People won't remember what you said. They won't remember what you did. But they will remember how you made them feel."
How true this is! Think about the last time you felt angry, hurt, or frustrated and you can probably associate a person with the situation. You will remember that person for the way s/he made you feel.