Peter Kreeft (Back to Virtue, p. 156-157):
Now why are we bored? Why this distinctively modern phenomenon? The very word for it did not exist in premodern languages! Above all, how do we explain the irony that the very society which for the first time in history has conquered nature by technology and turned the world into a giant fun-and-games factory, a rich kid’s playroom, the very society which has the least reason to be bored, is the most bored? Why is an American child playing with ten thousand dollars worth of video equipment more bored than an Indian child playing with two sticks and a stone?
The answer is inescapable. There is only one thing that never gets boring: God. The God-shaped vacuum in us is infinite and cannot be filled with any finite objects or actions. Therefore if we are bored with God, we will be bored with everything. For as Saint Augustine says, he who has God has everything; he who has everything but God has nothing; and he who has God plus everything else does not have any more than he who has God alone.