A childhood belief about birthdays

When I was about 4, and my sister was around 3, we were discussing christmas. It must have been pretty close, because we were getting very excited and discussing how many days were left. My mother heard us talking and said off-handedly that she hoped it didn't get skipped this year. We naturally asked what she meant, and she said, "Didn't you ever notice how sometimes when you wake up after going to bed on Wednesday, you wake up and it's Friday? Sometimes days just don't happen, and you can't get them back. It's really a shame when it happens on Christmas or someone's birthday." Well this was a revelation to us both (needless to say) and we anxiously held our breaths until Christmas was safely past. My mother forgot to tell us she had been kidding, and for several birthdays, Christmases, Halloweens, etc, the two of us worried if it would happen this time. It never did, and we eventually forgot the incident, only to remember it again and know it was all a joke at our expense.