As a pax, Albert 1989 - ASI - MPA (well, just short of) - Montevideo. 15+hrs and a brew. Worst bit was having to go back to ASI before trying all over again.
Also as a pax - Albert 2000 - Cairo West - Akrotiri - Souda Bay - Lyneham. OK, lots of legs but the best part of 36 hours stuck in the back of an aircraft sharing with a ship's engine.