For some unholy, around 2004, reason I wrote a template library that encoded all of the crystallographic groups as integer template arguments; I guess the idea was to allow automated mapping of any point in the unit cell to its canonical cell position. That'd let us compute crystallographic distances in something like O(log n) time, rather than O(n). (The usual way is to copy one of the points to every equivalent point in the unit cell, calculate every distance in all directions, and keep the minimum: 200+ distance calculations in the worst case; the copies were made via sequences of 4x4 matrix multiplies.)

Anyways, I deployed this software, and someone had a misstep, and the error message crashed the mainframe. I relayed this story to Bjarne around 2006, and he didn't find it funny — just frustrating.