I remember in my early teens helping my Step-Dad put together Santa's Stash for my little brother and sister. I've put together dolls houses, race car tracks, bikes among the many things they got over the years.
Traditionally the young ones would go to bed, then we would quickly assemble the presents that "Santa" dropped off. Of course, this is after we were 100 % sure they were asleep. We used to go to midnight mass as all good Catholics, but since that was the only time we went to church, we stopped that when l was around 14 years of age. Tradition was, at midnight on Christmas Eve, we would wake up my brother and sister saying, very excitedly, that Santa had come, and to come quick and see what he left.
Wiping the sleep out of their eyes, they would come down and look in wonder at all the stuff. It was pretty amazing the spread. Of course, the mandatory pictures would be taken of those first moments, and then as they opened the gifts from family.
Now as an adult, l realize why this was done on Christmas Eve. There were a couple of reasons. 1. My Opa (Dads, Dad) used to do this with his family, so my Dad passed it down 2. My Dad was like a big kid, and couldn't wait to see the look on our faces. 3. He had had a couple of drinks, and would like to sleep in in the morning. 4. My Mom was always the host of Christmas and would run around like a mad-women in the morning cleaning, prepping food, ordering us to shower and get ready for the company expected at 1pm.
Unfortunately things changed. We grew up, and everyone knew there wasn't a Santa Clause. Dad passed on and Mom spends Christmas in Florida. The glue that kept our family together became unstuck.