Psalm 118:24 -- "This is the day which the LORD hath made; we will rejoice and be glad in it."
One other thing my preacher said today. Notice the Psalmist didn't say "I feel like rejoicing so I will be glad in it." It was an act of the will! I choose to rejoice in this day. In everything give thanks, rejoice in the Lord always...you know, that kind of stuff!