At some point in your life, the things of this world will truly disappoint you and make you feel empty. It is then that you will say, "God, I want more." Your marriage is on the rocks -it is cold and lifeless. "I want more." Your job is unsatisfying. "I want more." Your children are undisciplined, in spite of your best, most prayerful efforts. "I want more." All of those things you hoped in to make your life happy and meaningful are now rusty, delapidated, and falling apart. "I want more, God. God?"
This is where where we need to walk carefully. There isn't anything wrong with wanting God to bless us or bring restoration to brokenness in our lives, but there is a danger found in wanting more of the right now. The danger is that our hearts are incorrigibly prone to seeking ultimate satisfaction in the things of this life.
We are prone to live as though this life is all there is, even if we believe differently in our minds. We may say to ourselves, "Seek first the kingdom, and all these things will be added...," but our hearts betray a different story. Our sight is focused and set upon the things of this life and our taste of the things of the age to come, no matter how utterly they are ours right now in Christ, is dull and small and overlooked. Our heart essentially is saying, "Yes, God... it is wonderful that things will be so nice some day," out of some sense of joyless, uninterested obligation, "but I want this thing right now."
With this, we are prone to forget God, at least functionally. We may have God for our times of prayer and for Sundays, but look at where our hearts are. What fills our prayers? Are they merely petitions to make our life go better, to make the things of this life more comfortable? That isn't all bad, but if that is the main pulse of our heart then we have somewhere forgotten God and the hope we have before us, and we are now asking God to serve the idols we worship, instead. It is, as the Puritan Stephen Charnock put it, "practical atheism."
In some ways, it may actually be more dangerous to have your life be perfectly happy and contented because the circumstances around you are just so. It is then that we are perhaps the most blind to how much we look to things in this world as our "god" and provoke the Lord to jealousy. At least when trials come we are forced to face what it is we really want, what our hearts truly cling to, and where our treasure really is.
As said above, it isn't bad, necessarily, to want more, and when things go awry it truly hurts -always. But ultimately the things in this world, as good as they are, or as broken as they can be, are meant to be appetizers to the main course... and nothing more. They are meant to be shadows, foretastes of what is to come. They are, in some ways, like manna from heaven as we tread through the wilderness on our journey to the promised land. They are temporary and point forward to the land flowing with milk and honey that is just around the bend.
Marriage problems or marital bliss? Remember that marriage is a temporary picture of a greater reality that is ours now, in taste, and to come in fulfillment when the Lord returns. Remember that it is a picture of the union between Christ and His Bride, us. That union will always be more glorious, more satisfying, more awesome than anything found on earth. Let the good times in our marriages remind us of that, and let that truth console us during the bad.
This does not mean we don't feel pain. Bad circumstances are not things we can shrug off stoicly. If we could, I would wonder if we love at all (the only way to avoid pain, that I am aware of, is to harden your heart and lock it up so tight that it will never love). But in the midst of the pain, in the midst of the loss and sorrow, let us be reminded of the temporary nature of this life and the hope that is ours, that everything in our life points to in some way. Let this truth console us in the midst of the trial we face. Rather than causing us to cling more tightly to the things here in this life, let suffering and loss cause us to set our eyes and hearts above (Col 3:5), where our true treasure is (Mat 6:21). The Lord endured the cross, despising the shame, for the joy set before Him. (Heb 12:2-3) We will enter into that joy, one day, the joy of our Master (Mat 25:21), and we taste of it right now, in part.