The worst immigration queue I've ever experienced was at London Heathrow where the line of passengers went all the way through the cattle-stalls, across the hall, down the corridors and almost back to the arrivals area. And to make matters worse the air conditioning had broken down and there was a line of off-duty immigration officers watching through a window, drinking tea and laughing. They're lucky it was armoured glass.
I've also had to put up with long immigration queues at both Sydney and Brisbane Airports and at Sydney _ though hopefully that may be easier now I've got one of the new passports so I can use the SmartGate _ on one occasion when I was only in transit there was even a long queue for the X-ray machine.
In the past I've had similar problems at Auckland Airport, especially when delayed flights have resulted in a mass arrival of passengers, but since the new immigration area opened and the airport introduced a new streamlined system of processing I've been very impressed. Singapore and Hong Kong are also places where you rarely have to wait.
I simply can't understand governments and airports who fail to understand how important it is to make tourists feel welcome on arrival (and, for that matter, on departure).
Where's the sense in spending a whole lot of money inviting tourists to your country and then getting their visit off to a bad start (or finish) when they do?
What airports have the worst immigration queues in your experience?