The world is constantly telling us all the things we need, and it's easy to listen. The voices are loud. But the still, small voice of the Lord says we only need Him. When we continue to try to fill ourselves with the things of this world, we'll continue to be disillusioned and empty.
There's always one more thing to get, one more achievement, one more experience.
Contentment cannot come that route, and "godliness with contentment is great gain." (I Timothy 6:6)