From commenter Adam G:
People content themselves with shallowness because they are afraid.
They are afraid that if they confront ultimate questions they will find that life is meaningless.
It isn't a conviction of nihilism that makes our culture the way it is. It's a worry that nihilism may be right.
This analysis strikes me as highly insightful; and it has lessons.
Christians need to demonstrate by their living that there are real answers to the ultimate questions- I don't mean that this should be acted or expounded, but that the whole mode of interaction should be suffused by the light of these answers.
But this is not the same as being able to answer any and every question, especially not to answering every question to the satisfaction of the questioner - that is impossible, and the process of questioning tends to reinforce the false world view of the questioner.
Rather it is a matter of letting it be known that a Christian does have the answers, that the answers are wonderful - and that they are real.
We are talking about realities - and the discussion is about realities.
Realities does not mean that the evidence for this interpretation of reality is overwhelming and irrefutable and compels acceptance - but that Christian answers are solid in every way.
(Christianity itself is irrefutable - but the evidence-for Christianity is not so. That is in the nature of things, including science. Any specific item of evidence can always be challenged, reframed, refuted - thus evidence as a whole can always be broken down into specific items and - supposedly - 'refuted' piecemeal.)
But the most important way that Christian answers are solid is that:
Being Christian enables a person to confront the ultimate questions of life - fearlessly.