When I was young I believed that Christmas was the last day of the year. It made sense, I was a child of a practicing Catholic family and I thought Jesus's big day was supposed to be the last day of the year. So what were those couple of days in between Christmas and New Year's? I believed those were just leftover days, as if someone didn't do their calendar arithmetic correctly.
A childhood belief about general

others believed things like this
- I believed that Robins hibernated throughout the year and only came out at christmas. Anon
- Abba - Happy New Year
"Kangaroo year,
Kangaroo year..."— Santa Puncher - that we celebrate New Year's because it is the day that Jesus had his brit (circumcision)Anon
- I believed that pigs could actually fly. I'm 13 and found out this year that they can't.— Boy I'm Blonde
- I believed that those who died would be resurrected a year later.— crow
- i thought I got one year older when my family sang the birthday song.— I am the ghost