Calendars are set out so that, at the end of the month, there are some blank boxes in the grid. For example, if May 31 is a Monday and June 1 a Tuesday, there will be a number of blank spaces after Monday 31 and also before Tuesday June 1. When I was 5 or 6, I believed that those were extra days that had no name. I thought it was a totally wasteful way to portion time, because there were all these blank days we had to live through to get to the next month.
A childhood belief about general

others believed things like this
- I thought the Til Tuesday song said "Books are scary!", rather than "Voices Carry"Anon
- My cousic used to think he was older than me because his birthday was in June and mine was in December.— //**...Ethan...**\\
- My sister believed that october was the 10th month!— Sally
- I used to believe that I was older than my brother because I was born in June and he was born in OctoberAnon
- The moon was actually either a sugar cookie or a banana, depending on the time of the month. — Jessica Aspra
- I convinced my sister that chocolate milk was made out of Keebler cookie elves, she believed me for a month— Rainbow Steel