Maranasati – Mindfulness of Death is called The Supreme Mindfulness Practice by the Buddha. It teaches us to let go and value the fullness of our impermanent lives. Contemplating death reveals the paradox of dharma and death which are experience and known both personally and impersonally.
According to a recent Harvard study, the wandering mind is the cause, not the consequence of our unhappiness. And the "doing mind" - analytical reasoning, problem solving, figuring things out - does not lead to wisdom!