Prayer is the raising of one's mind and heart to God.

In prayers we can 1) praise and adore God, 2) ask God for something, 3) thank God for something, 4) Apologize 5) Listen to God 6) Just be with God

What prompts a person to pray?
We pray because we are full of an infinite longing and God has created us men for himself: "Our hearts are restless until they rest in you" (St. Augustine). But we pray also because we need to; Mother Teresa says, "Because I cannot rely on myself, I rely on him, twenty-four hours a day." [2566-2567, 2591]
Often we forget God, run away from him and hide. Whether we avoid thinking about God or deny himhe is always there for us. He seeks us before we seek him; he yearns for us, he calls us. You speak with your conscience and suddenly notice that you are speaking with God. You feel lonely, have no one to talk with, and then sense that God is always available to talk. You are in danger and experience that a cry for help is answered by God. Praying is as human as breathing, eating, and loving. Praying purifies. Praying makes it possible to resist temptations. Praying strengthens us in our weakness. Praying removes fear, increases energy, and gives a second wind. Praying makes one happy. (YOUCAT question 470)

When someone else is praying, you should not distract them.  If you come into the classroom when the class is in the middle of prayer, stop inside the door and join in the prayer.