I have never worked in mcdonalds but I did work in a big supermarket for a couple of years.
Fun things that happened while I worked there included -
Putting a cardboard cut out of the cilit bang man behind a checkout and watching an old woman queue up to be served by him. Also adding C. Bang to the roster then having to explain to the manager that he had phoned in sick when he asked where the new starter was.
Seeing how many copies of the Crazy Frog debut 'crazy frog presents crazy hits' we could shift by dropping copies of it in unsuspecting customers trolleys.
A guy hiding under a large box and scuttling after customers. Stopping everytime they stopped and looked around.
Fun tannoy announcements. One guy got sacked for belting out his own rendition of shoplifters of the world unite on a Sunday afternoon.
There were loads of loads of really mental people there. Including 'the chicken baster' an old fellah who allegedly got caught buggering a frozen chicken and 'Mental Martin' who licked raw eggs of the floor rather than cleaning the mess up.
I'll also never forget the exchange I had with the outgoing head of HR's second in command when I refused to sign her leaving card on account of not really knowing her. She said 'well maybe if people like you had tried to get to know her she wouldn't be leaving!'
There was lots of other stuff too.