I once lost it (as a pax) on a DJ flight during the demo... now I am normally really serious but the song playing on the PA reminded me of something really funny... the poor girl kept looking from the cabin to me, I was hiding behind the seat in front, tears down my face and stuffing my hand in my mouth to keep quiet... you know sometimes you just 'get the giggles' so to speak... I couldn't help it... I felt SOOOOOO bad....
Later I did go explain that I wasn't laughing
at her... when I told her what it was, she thought it was funny too!!!