No problem on the Lord's day.

The Purpose of Man's Existence
Lesson 1 from the Baltimore Cathechism

3. Why did God make us?
God made us to show forth His goodness and to share with us His everlasting happiness in heaven.

Eye has not seen nor ear heard, nor has it entered into the heart of man, what things God has prepared for those who love him. (I Corinthians 2:9)

4. What must we do to gain the happiness of heaven?
To gain the happiness of heaven we must know, love, and serve God in this world.

Lay not up to yourselves treasures on earth; where the rust and moth consume and where thieves break through and steal. But lay up to yourselves treasures in heaven; where neither the rust nor moth doth consume, and where thieves do not break through nor steal. (Matthew 6:19-20)

http://www.catholicity.com/baltimore-catechism/lesson01.html