Here's a few that have made me chuckle over the years -
pax (pointing to airshow on main cabin screens and pushing his inseat TV controls while looking a little miffed) asks "can I please have the remote - I can't get the channel to change".
pax (business class) asks for the red wine bottle, looks at the label, notes the vintage and hands me back both the bottle and his glass "you can't serve me that - it's old".
pax (business class) gives me back his champagne and complains "there are too many bubbles in it".
Crew "Caviar Sir?" Pax, "oh yes, I love it. Give me everything, but none of that black stuff".
A colleague was in the cabin with tea and coffee pots in her hands when a passenger asked her for a pen. Without missing a beat my colleague replied "sure, hold these", and shoved both pots towards the suitably embarassed passenger.
But my favourite story would be my own inability to understand what the passenger was trying to tell me - just before I took my duty free cart into the cabin the PUR announced that Channel 5 was not working on the inflight entertainment system. On arrival in the back galley I had a passenger approach me repeating 'channel 5, channel 5'. I apologised and explained we were aware of the problem with the system, before I realised he infact wanted to buy a bottle of 'Chanel 5' from me!! Bless.