A few night ago myself and a fellow forum member both did a night sea trouting session.
i was happily fishing a pool while he was approx 100yards upstream fishing another pool.
now flowing water makes a noise although the night was quiet you couldn't hear the person next to you speak.
i proceeded to fish with the utmost concentration as one does giving a quick glance over my right shoulder to see him still fishing.
i continued to fish when i head a voice in my ear asking 'any luck'
well i kid you not i gave out the biggest girls blouse scream of my live words to the effect of BWAAAAAAAAAAAAAA.

and if any one else was witin the vacinity of z scream they would probably thin wtf is going on.
i turned to see z friend standing happily laughing at the same time puzzeled as to my reaction of not hearing him walking behind me.
we still laugh to this day and that is the first genuine time i felt my sking leave my body absolutely hillarious.