I don't think we can ever be too kind.
It goes a long way.
My husband and I were talking just yesterday about a man who died that was a high school friend of his. He ended up in a wheel chair in his 30's from a stroke and when I first met him, he was just so nice. Every time I saw him, he was so kind to me. This man was in a wheelchair, yet he was always smiling and being kind to everyone he met.
It makes me wonder what I would be like in his shoes?
My son graduated from high school a few months ago and the speaker talked about kindness. She said "remember, kindness goes a long way". That was what she wanted to leave those seniors with....a talk about kindness.
Think about it. How many people do you specifically remember in your life because of their kindness? (or their meanness?)
I go to see a particular butcher because he's so nice to me. I avoid grumpy people. I love people who smile. When someone is kind to me, it goes all through me and makes me feel good.
Try it and see how good it makes you feel. It's heartwarming to be on both ends of kindness--the giving and the receiving.