Because

...because we remember what it felt like to want to look inside
...because we remember when it felt impossible to wait another minute
...because we remember how hard it was to sleep
...because marshmallows work for snowball fights when Christmas is warm
...because we couldn't wait to open it either
...because we learned to hide our feelings...too well
...because they haven't learned to hide theirs...yet
...because we have to believe the miracles will come
...because we're so tired, we can hardly stand it sometimes
...because they don't know what that kind of tired feels like yet
...because we miss our own grandma
...because the food always tasted better when mom made it
...because our aunts and uncles had more energy than our moms and dads
...because our moms and dads showed us the way
...because we heard the story of God Who came to earth as a man
...because we learned about the wise men who gave gifts
...because we learned about a Saint who gave gifts

Sometimes we just can't remember why....so we do it again and it helps us remember...and we're thankful all over again.