I always thought that after 1999 it would be 1990 again, but with different months and days of the week
A childhood belief about general

others believed things like this
- I thought that "tomorrow" was one of the days of the week— Frank
- I once refused to believe in Thursday. I'd heard there were seven days in a week, but could only name six.Anon
- I got the 1990s and 1900s mixed up, so I thought people wore that fancy old-fashioned garb in the 1990's.Anon
- My sister used to think that because I was 15 months older than her, I would die 15 months before her!— Nicola Braden
- I thought the guy who got shot at the beginning of Gunsmoke was replaced every week by a live guy.— Monica
- I thought that days had 100 hours in them. Very surprised to hear there were only 24.— Cassiopeia