In a pluralist culture such as our own, in which we have regular dealings with persons outside of our own religious tradition, apologetics can be a helpful and necessary tool. People want to know why you believe in Jesus, what good is there in the Christian religion, etc. This is especially important because stereotypes abound, and it is most probable that the average person on the street does not have a great grasp of what the Christian religion is all about.
But those who've studied the arguments for and against Christian faith also know that arguments do not always work to convince the other person. There are some characters who are so dead-set on opposing Christian faith that they are willing to accept any alternative, however absurd, just so long as it negates Christianity. So we have the "Jesus mythicists," who don't even believe that Jesus existed, and that the gospel stories are based on ancient pagan mythology -- absurd as that may obviously seem to anyone who has more than a passing familiarity with the gospel texts themselves.
There is a kind of apologetic testimony that is less academic and abstruse than some of the arguments the philosophers and theologians consider. It is a kind of argument from personal experience. This is amply illustrated in the story in the Gospel according to John, chapter 9, in which Jesus heals a man who was blind from birth on the Sabbath. The people took him to the Pharisees, who debated about the nature of this tremendous miracle:
Some of the Pharisees said, "This man [i.e., Jesus] is not from God, for he does not observe the sabbath." But others said, "How can a man who is a sinner perform such signs?" And they were divided (John 9.16).
So the Pharisees debated among themselves for a while, and then asked the blind man to give his opinion:
So for the second time they called the man who had been blind, and they said to him, "Give glory to God! [i.e., Tell the truth!] We know that this man is a sinner." He answered, "I do not know whether he is a sinner. One thing I do know, that though I was blind, now I see" (vv. 24-5).
The answer is short and sweet and to the point, but also poignant! I don't know whether Jesus is a sinner; all I know is now I can see, when I was blind my whole life! That is the kind of argument from personal testimony that might prove most effective, especially when it is used in discussions with close friends who notice your different way of life. Something about you is off, something about you is just different from the rest of us. What might it be? The answer, of course, is that you know Jesus, and this knowledge and friendship with him is transformative in a unique way.