Thirsty's story of thinking the engine was diassembling itself, reminded me:
I recall my nephew, when a 'boy pilot' with SAA in their 747 fleet (about 15 or so years ago). On the European runs, the supernumerary would sometimes be sent to have a rest period in a spare First Class seat. On one trip into LHR, after he'd done his shift he was told to stay there for the landing and enjoyed breakfast sitting in 1D.
During the approach, he was horrified to hear loud banging and crashing sounds under his feet and thought the aircraft was disintegrating. Until he realised it was the nose gear going down ... He'd never been sat there before!!