Summarize this article in one sentence.
Any time you interact with another person, take a second or two to acknowledge him. Because you never know what is going on in another person’s life, a simple “hello” or “thank you” can go very far in making the person feel worthy and happy. In turn, the person’s reaction may bring you joy with the response you get.  Start off any interaction with a smile. It doesn’t even need to be a big, toothy grin. A smile to a person you walk past may get a smile in return. Generally, the nicer you are to others, the more they will want you around and you’ll experience the positive social consequences. Make eye contact whenever you can. Consider greeting others with a cheerful “hello.” Remember to say “please” and “thank you.” Saying these things and incorporating positive behaviors become a habit over time. Even at tough times, they can offer a glimmer of humanity to other people who are struggling. Doing something nice for another person, like offering a compliment or paying for her lunch, can bring both of you a lot of joy. In any situation, consider making a small and kind gesture to another person. Not only will this bring the other person joy, but may also brighten your spirits. Keep in mind that you don’t have to do something grand. Buying coffee for a friend or colleague who is having a hard time or giving someone a kind word can help the other person—and you—be joyful. There are a lot of people in the world who are less fortunate than you. They may not have a home, job, or their health. Giving some time to these people can give them a glimmer of hope and joy and make you feel great, too. Offer your time to a health facility or organization that provides aid to those less fortunate than you. Consider working at a place where your skills may be especially welcome. For example, if you like to paint, you could volunteer to paint with sick children or the elderly. You could also help individuals living in shelters develop their job skills.

Summary:
Acknowledge a person’s presence. Offer simple acts of kindness. Volunteer your time with the less fortunate.