Smiling at people lets them know that you are pleasant. Look the person in the eye and give them a small smile or a wide grin – it doesn’t matter which. This sets the mood of the encounter and usually encourages the other person to smile back. This also helps the person feel comfortable around you. If they do not smile back at you, then maybe they are just having a bad day. That’s okay; being nice doesn’t guarantee a positive response, but it usually helps