I think if you give a simple smile to someone they will absolutely respond with a smile too. This is a simple act of showing how grateful you are. But sometimes it's hard to smile if we have a problem, isn't it? Usually, for Christians we have the reason to smile every moment. Perhaps, we are experiencing problems yet we can smile because we feel the peace from God that He is with us. We are comforted that God cares for us. This is what we want to show to the world. This is the reason that we need to smile every moment of our lives.
This is the time we will tell those who are in trouble to depend on God too. That there is God who cares for them.
Have you ever tried to use free smileys at myemoticons.com when you are sending messages to your friends in social networks you are in? Maybe if you use smileys and your friends see it, they will feel your presence even they are in sadness or they experienced problem in life. If we send a simple smile to show our deepest emotions for them they will be at ease. Let them know that you cared for them. Simple smileys will give a great impact in their lives if it was given by heart. Can you try that?