After every flight, Qantas pilots complete a form called a "Gripe Sheet" which tells the mechanics about problems with the aircraft.
The mechanics correct the problems; document their repairs on the form and the pilots then review the Gripe sheets before the next flight.
Never let it be said that the ground crews lack a sense of humour. Here are some actual maintenance complaints submitted by Qantas' pilots (P) and the solutions recorded by the maintenance engineers (S)
Apparently Qantas is the only major airline that has never, ever had an accident.
P: Left inside