When I was working in one particukar institution, I used to have a colleague who was somewhat a Christian. He believed in Jesus Christ but hated affiliated himself with any church. However, he used to tell me about his friend who worked in another company. That person was a Christian - and his life spoke it: he was kind, deligent a treated people under him with utmost respect and much more. What striked me was that the persons working with him and spoke well of him were not Chrstians. They were impressed by his life. Ewnetegna pente new' yelu nebere. I used to think 'what a testimnoy!'.
In a nutshell, non Chrisitan will be in awe when Chrstians show love, mercy joy, faith and many other fruits of the Spirit rather than say too much about Christianty; I believe it will lead them to Christ eventually.