How many times have you had a bad opinion about somebody that went from bad to good once you got to know them a little better? What changed? The person didn't. They're still the same person. Your attitude about that person changed. A positive attitude puts a different light on everything and everybody.
John C. Maxwell in his book Today Matters says, "One of the secrets of maintaining a good attitude is valuing people. You can't dislike people and have a good attitude at the same time. Think about it. Have you ever met anyone who always treated people badly but had a positive attitude? Likewise, you cannot have a bad attitude and encourage others at the same time. Encouraging others means helping people, looking for the best in them, and trying to bring out their positive qualities. That process drives negative thoughts right out of your head.
Your interaction with others sets the tone of your day. It's like the music of your life. When Your interaction with others is poor, it's like having to listen to cacophonous music. But when you place a high value on people and you treat them well, it's like listening to a sweet melody as you go through your day."
Walt Emerson said, "What lies behind us and what lies before us are tiny matters compared to what lies within us."