"Death and Destruction are never satisfied, and neither are the eyes of man." Proverbs 27:20
It's human nature to always be craving but never be content. Those cravings indicate that we're hungry for more meaning, purpose or results and we have God to thank for that. The problem is that we turn that hunger toward possessions, people and personal agendas instead of letting that holy discontentment drive us towards God and His Kingdom. A maturing relationship with God will shine light on our dissatisfaction and direct it toward the things that really fulfill us. Be driven by a desire for God, He's the only One who satisfies.