Resurrexit Sicut Dixit! We don't take enough time to be joyful. Joy is not mere happiness, nor is it happiness despite the darkness around us. Joy is, in a sense, a Christian response to darkness.
The liturgy of Tenebrae (Latin for "darkness"), which dates back to the ninth century, is a special expression of Matins and Lauds unique to Holy Week. The psalms chanted during Tenebrae ground Our Lord's Passion in the context of Salvation History.
We encounter Christ's Passion in every Mass, but the liturgies of Holy Week make the reality of Christ's Passion so clear to us.