I think it's the excitement of flying something other than the "usual" airlines that run a certain route.

AI and SQ run a few of those flights, LAX-FRA, JFK-FRA, ORD-FRA, IAH-DME, and others. . .
JL: MEX-YVR
And then LH has all these short hops in the Middle East / Africa that seem to change routing and book-ability pretty quickly.