Not only will our human flesh and hearts one day fail, but even the earth itself will one day die: “the earth shall soon dissolve like snow.” Not only is each human life temporary, but all life on this earth will soon be finished. When Jesus comes again as righteous judge, he will fold up the heavens and earth like a garment and put it away.
This is sobering, and all the more so when Paul reminds us that “flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption” (1 Corinthians 15:50). We are not, in our very best situation on earth, suitable for heaven. The very holiest saints are not pure enough for heaven; the very best athletes are not fit enough for heaven; the very best earth-treasures are not imperishable enough for heaven.
Take a helicopter pass over your life: what are the mountains, the big and defining objects that clearly dominate the landscape of your thoughts, your time, your pursuits? Are you so invested in this world emotionally and financially that leaving this world is the worst thing you can imagine? Are the great treasures of your heart primarily earthly? If so, they are temporary. That is the point: whatever is perishable cannot inherit imperishable, will not survive the resurrection, will not belong in heaven.
But everything in Creation therefore is only truly meaningful when it is used to bring God glory. Physical things—including our bodies—have no value in and of themselves; they derive their value from their connection with the kingdom of God.
So we should not get so attached to things that are in their very nature passing. It is like falling in love with a snowman — come Spring, it will melt away and you will inevitably be left heart-broken.