In the summer of 2004 I flew 6,000+ additional miles on a UA HKG-SFO-LHR routing (instead of HKG-LHR direct): 12,294 miles v 5,994 miles - all in economy.

At the time I had job interviews arranged just 48 hours apart in Hong Kong and England; the first interview paid travel expenses, the second one didn't (I was living in CHS [SC, USA] at the time). So I arranged an all-UA CHS-ORD-HKG-SFO-LHR-IAD-CHS itinerary at a bargain price - and managed to recoup the entire cost. ^