My mom always says this. This is why she never minded teaching 4-year-old Sunday School. She knew she was making an impact, even if they didn't remember what was taught that day, they knew she cared for each and every one of them.
"Always be the better person even when the other person doesn't deserve your kindness, you will always feel great about yourself knowing you've done the right thing, knowing you made Jehovah happy." I ALWAYS tell my girls that.