'I'm going to ring up your last boss and ask why you left the airline. What is he going to say?'
That one is a pig if you left on bad terms . . .
Probably the worst was asked by a lady psycholigist as part of the Britannia selection:
'How long can you afford to stay out of work?'
Well out of order that one. A deliberate play to see how much money you have. The issue being that if you are well off you might be a more independently minded employee.
The only answer to that sort of rot is a polite:
'I'm sorry, but that is more information than you need to know'.