At some point, you've probably heard the gospel presented like this:
2. The wages of sin is death (death is "code" for hell)
3. But (good news!) the free gift of God is eternal life in Christ Jesus our Lord (eternal life is "code" for heaven).
-- SO --
4. By God's grace alone through faith alone in Christ alone you can go to heaven instead of hell when you die.
That is most certainly great news. That is most certainly true. But, it's also most certainly only part of the story.
I don't mean to nitpick, but "death" isn't just code for hell; "eternal life" isn't just code for heaven. The bible says that, as long as we are apart from Christ and still in our sin, we are "dead" right now (Eph. 2:1-2; Col. 2:13, for example). The bible also says that, by grace through faith in Christ, we are "alive" right now (Eph. 2:5; Col. 2:13, for example). Death and life are as much metaphysical as they are physical. Everyone who's ever lived knows there's a difference between physically being alive and really living. What the gospel offers is abundant life now and perfect life in eternity. The good news of the gospel is that you don't have to wait until heaven to start really living.
When we make Christianity about heaven and hell, just heaven and hell, Christianity becomes somewhat irrelevant to the here and now. If Christianity is about going to heaven, and I'm going to heaven no matter what I do once I'm saved, then why go to church? Why read the bible? Why even try to do the things Jesus commanded in the sermon on the mount? It's hard, it's no fun, and it certainly isn't living. Maybe I'll smile more, dress nicer, and do enough religious stuff to keep God happy -- I owe him one -- but beyond that, what's the point? For now, I just... wait.