What makes our heart restless?

Is being penniless make our heart restless? I don't think so. What about having problems? Could it make our heart restless? Well, partly it will. But not all people with problems have restless hearts because these people knew that, each man's problem is enough for him to carry on. If that is so, then what makes our heart restless? Do you want to know what were my folks answers? They said, first is discontentment. According to them, even if a man has everything and yet he is not contented for what he has, then he will not find rest in his heart and continues seeking something that will fill in his emptiness. Another is hatred and anger. An angry man easily finds enemies. He always has this feeling of animosity not only to his enemies but also to the people who are in contact to his foes and thinks that these people are against him too. These unhealthy feelings of hatred and anger also make our heart uneasy and restless.