Most irritating - got to be Accra, Ghana. Where else would you have 2 flights, both full DC10's, one to JFK and one to LHR, checking in at 1 desk. MANUAL CHECK-IN TOO!! 500+ hot & sweaty bodies trying to get rid of bags. I'm sure I joined the queue on 17 different occasions. And immigration were a different class. Number of officers on duty decreases as the number of passengers increases. Logic learnt from the British Post Office I feel.
SIN takes some beating in the best stakes. Loads to do and easy to find things.