Do our lives make sense to the world? They shouldn't - not if we're Christians.
In 1 Corinthians 15, Paul is addressing believers in Corinth who were saying that there is no resurrection of the dead. He explains that if there is no resurrection, than not even Christ has been raised, and if Christ has not been raised, then our faith is in vain, we are still in our sins. He goes on in verse 20 to declare that Christ has been raised, and that in Him all (who are the elect) will be made alive. Because Christ has been raised, we shall be also. We have a future hope. But what if we did not have this hope? Look what Paul says in verse 19:
"If we have hoped in Christ in this life only, we are of all men most to be pitied."
Did you catch that? If our hope lies only in this life, we're to be pitied. That's legitimate. Paul certainly did not subscribe to the "health, wealth, and prosperity" brand of Christianity. Picture this - you're a Christian, and the world is watching you. You have a gorgeous home, an awesome car, a perfect family, good health, lots of money to spare, and you "hope in Christ." In fact, you have all these things because you're a Christian and being a Christian means you're just blessed that way. Then you die. Would the world pity you? Of course not! Even if they thought your belief in Christ was ridiculous, they wouldn't pity you because you had all the stuff they want - the stuff that, for them, is the mark of a life well lived.
But that's not the picture Paul is giving. He's implying that as Christians, we live (or should live) in such a way that doesn't make sense apart from this future hope that we have - an eternity of joy in God that far surpasses any sacrifice we make on this fleeting earth. Some things just don't make sense to the world - denying self, laying down your rights to serve another. This is "fleshed out" in many ways, since we're individuals in unique settings...
It could mean refusing to climb the career ladder, because it would mean less time with the family, less time to serve the Lord. It could mean not pursuing something the worlds values - like an impressive college or university degree - because the Lord has called you to do something else. For a mom, it could mean staying home to faithfully raise up godly children, rather than pursue the double-income dream. It could mean staying home on a Friday night to study the Bible rather than going out with friends because you have a thirst for the Word, and you've decided to make that a priority. It could mean sending extra money to a missionary rather than buying that new pair of jeans you've been eyeing. It could mean a million things, but the important thing is to be sensitive to the areas God's calling you to be different in, and to live that out faithfully, by His grace.
We have a future hope, and it will be worth it!
Therefore, my beloved brethren, be steadfast, immovable, always abounding in the work of the Lord, knowing that your toil is not in vain in the Lord. 2 Cor 15:58
All these died in faith, without receiving the promises, but having seen them and having welcomed them from a distance, and having confessed that they were strangers and exiles on the earth...
But as it is, they desire a better country, that is, a heavenly one. Therefore God is not ashamed to be called their God; for He has prepared a city for them. Hebrews 11:13-16
Note: Just to avoid misunderstanding, living for eternity does not mean that we are not to enjoy the good gifts God gives on this earth - it just means that they are not to be the ultimate focus.