Yes. As Christians we are commanded to love one another and be a light to the world (easier said than done). Alas, this quality does not show through in many a Christian. No one but God is perfect. Our job is to walk in obedience to God as best we can (some days are better than others).

You are the light of the world. A city set on a hill cannot be hidden; nor does anyone light a lamp and put it under a basket, but on the lampstand, and it gives light to all who are in the house. Let your light shine before men in such a way that they may see your good works, and glorify your Father who is in heaven. Mat. 5:14-16 (NASB)

As for those who do not believe in God, such a belief is obviously contrary to Christian beliefs. Thus, we do in fact believe that they are wrong in thinking so, and that not seeing God personally is not an excuse for non-belief as noted in Paul's letter to the Romans:

For since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse. Rom. 1:20 (NASB)

I'm not an expert in the subject, so I may not be presenting a particularly compelling case for faith. However, I make no apologies for being a Christian. It is not necessary for you to agree with me, you are free to believe what you like. When I die, and there is no God, then I haven't really lost anything. But, if I die and there is a God, then I have eternal life and a nice place to live.