The best part of mine was being told to park next to an airliner at one stop and being greeted as an equal fellow pilot by the captain thereof ... OK, so it was "only" an Air UK shed[1] at Norwich, but still a real airliner.
And the hardest bit was trying to find someone at Norwich to persuade to let me go back airside when I'd finished my cup of tea.
[1] Or was it one of the Fokkers? - don't really remember.