People are emotional creatures. When you’re having a discussion, creating a piece of art or helping someone you love, be mindful of your emotional impact on your fellow human beings. As Maya Angelou said: people will forget what you said, people will forget what you did, but people will never forget how you made them feel.
How to Win Friends and Influence People (book) by Dale Carnegie.
Origin of the Maya Angelou quote (quoteinvestigator.com).