It seems that one particular Christmas Santa was rushed and harried trying to get ready for his annual trip to deliver gifts to the world's children. He told Mrs. Claus to wake him at 5 a.m. and to have his breakfast ready with a lunch to take along. He then went to his workshop and told the elves to have all the presents packed in the sleigh and the reindeer harnessed at 5:30 a.m.
At 5:30 the following morning he awoke and jumped out of bed furious with Mrs. Claus for not awakening him on time. His mood worsened when he realized she had fixed neither his breakfast nor his afternoon meal. Then he ran out to his sleigh only to find that the elves, drunk from partying all night, had no presents packed and the reindeer were running loose in the pasture.
About this time a little angel walked by dragging a large Christmas tree. Santa tried to ignore her since his mood was so foul but the angel spoke up and said, "Santa what should I do with this Christmas tree?"
And that is why there is an angel on the top of the Christmas tree.