Walkaround:
Ice on wings (instructor: "well done for spotting that, let's go flying anyway")
Not enough oil (more than once, fixed by a man with an oil can)
Squeaky aileron hinges (fixed by a man with a different oil can)
U/S beacon (instructor: "do the strobes work? OK, I suggest you notice the beacon failure when you come back from flying")
Earthing braid on elevator almost worn through, only a couple of strands left (instructor: "it's OK for today, but we'll certainly put this in the book for the next check")
Water in fuel (only found once, but took a bit of clearing)
Fuel quantity wasn't what I expected from the paperwork (in both directions, including once so empty that the previous pilot was bloody lucky to land it normally)
U/S handbrake (but if I'd been properly awake I'd have known that before getting into the aircraft, as it was properly documented in the paperwork)
After starting:
Front suspension bottoming out (rejected aircraft, took a different one)
Failed power check (instructor showed me how to burn the crud off the plugs)
After take-off:
Oil pressure well above upper red line (instructor took control, flew circuit, landed, gave aircraft to engineers; turned out to be an instrument error mis-reporting a healthy engine) (neither of us noticed this during power checks or on the runway
)