For me it came from the material. It was so well written and brought the opportunity to work with great actors. And of course the opportunity to 'mince about' was an added element that I wanted to take advantage of!
I suppose there must be some way in which I'm compelled to show some side of myself - or of people - that's paranoid and fraught and beleaguered and downtrodden, just as Tom Cruise wants to show that he's terrifyingly upbeat and terrifyingly heroic all the time.