Like my landlady thinks 29=30, and I can't get it through her head that if she gave me 30 days on the 26th of February, which was a Friday, I'm only at Day 28 right now. Like, I don't think she grasps the concept of seven days existing per week. She keeps insisting tomorrow is day 30.
ETA: And no, this isn't a sheer misunderstanding, this is stupidity. I walked her THROUGH THE CALENDAR ON THE WALL and she still doesn't understand.
Alternatively, what is your favorite Spice Girls song?