Santa came to our house on the eve of Christmas Eve each year, the night before December 24th, a whole day earlier than for everyone else I knew. My mom explained to us that there were way too many people in the world for Santa to visit on one night, so he had a special Christmas Eve list and we were on it. We also opened our presents ahead of tradition on Christmas Eve night, right after dinner, not the next morning like everyone else. But we didn't ask for an explanation for that difference, not after waiting an entire day, from dawn to dusk, with unopened Christmas presents in the house.
Yes, later when we were older we learned that mom had practical reasons for breaking with tradition. She wanted to avoid squirmy children at church on Christmas morning. She had learned that, whether presents were opened right before or immediately after church, they danced too much in the eight wee little heads she needed to keep calm through Christmas morning mass.