This feeling of significance, Tim Keller says in a talk by him I just heard, is what is meant by the term "justification". In the Christian worldview, justification is like getting a high five--a standing ovation, even--from God. It is not just finding meaning, it is being counted worthy and accepted by the Source of all meaning. I think it is the most fundamental need of every human being.
And how do we get this fundamental affirmation, this justification? Many people (Christians included) think it's by our moral performance; our ability to conform to a list of do's or don'ts. This could be from the Bible, from some other author, or from osmosis of the culture around us. Those who don't look there often look for approval from friends, significant others, or family. Or having a lot of money. Or being an ambidextrous piano virtuoso. But if you are conscious of your need for justification, and how the things you look for it in inevitably fail, then the gospel is the best news in the world. Justification is free! Completely free! There is nothing you can do to deserve it, or not deserve it! Paul writes in Romans 3:21-24:
But now a righteousness from God, apart from law, has been made known, to which the Law and the Prophets testify. This righteousness from God comes through faith in Jesus Christ to all who believe. There is no difference, for all have sinned and fall short of the glory of God, and are justified freely by his grace through the redemption that came by Christ Jesus.("Righteousness" here has a similar meaning to "justification") I'm finally starting to really "get" this definition of justification and it's amazing. I still have a lot of processing to do in answering those first four questions. Even though these other sources of meaning we hold onto will inevitably leave us hanging, it's so hard to let go of them. Many of them are genuinely good things, like family or a pleasant personality. Of course you shouldn't walk out on your family or become a jerk if you put too much importance in these things; even as we keep them in our lives, we're challenged not to make them the one thing that we need.
One other cool thing Tim Keller mentioned was the difference between justification and forgiveness. Christians believe that we deserve death and eternal separation from God for betraying Him and sinning, but in Jesus we can be forgiven and get a clean slate--it's part of the package along with justification. That's great, but they aren't the same thing. Keller drew up the analogy of a prisoner pardoned and released from jail, but who is now homeless, jobless, responsible for making his way in the world and proving himself. This is what forgiveness alone would be like: sure, we're free now, but we're on our own and we'll just fail again. Whereas justification is like getting the Congressional Medal of Honor and everything else they can give you (only better); it's receiving all this honor and affirmation from outside ourselves and knowing that yes, we really are worth something.