"If the way you live your life as a Christian can be explained in terms of you, what have you to offer to the man who lives next door?
The way he lives his life can be explained in terms of him, and as far as he is concerned, you happen to be "religious"--but he is not! Christianity may be your hobby, but it is not his, and there is nothing about the way that you practice it which strikes him as at all remarkable.
There is nothing about you which leaves him guessing, and nothing commendable of which he does not feel himself equally capable without the inconvenience of becoming a Christian.