I thought that Saturday was actually "Sadderday" because it was some how sadder than the other days of the week!
A childhood belief about speaking

others believed things like this
- I thought that "tomorrow" was one of the days of the week— Frank
- I always thought that after 1999 it would be 1990 again, but with different months and days of the week
— optional - I once refused to believe in Thursday. I'd heard there were seven days in a week, but could only name six.Anon
- 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
- back in the days i thought the world was black and white like in the pictures— compaq