Society bristles with enigmas which look hard to solve. It is a perfect maze of intrigue. Honoré de Balzac
Do you know why it's so hard to solve a Redneck murder? 'Cause there's no dental records and all the DNA is the same. Jeff Foxworthy
Well, some mathematics problems look simple, and you try them for a year or so, and then you try them for a hundred years, and it turns out that they're extremely hard to solve. Andrew Wiles