Story posted anonymously with the permission of the author
I remember when I was a kid, my parents would hold these stupid BBQ lunches (I hated them, now nobody dares invite me to such behemoths). There was one family that was always 60-90 minutes late.
So I tabulated their delays according to date, and studied the traffic patterns on each date. I then derived an algorithm by which they could be on time every time. I gave it to them. They were horrified and my mother later beat me.
I never really knew what I did wrong.