When you get on the flight deck and there is a significant snag well written up, plenty of detail with a FRM code but he hasn't bothered radioing in so that you could get a head start on the problem.
The one's who snarl and bark because when they've called you pre departure with a defect, you immediately reach for the MEL. Isn't it the intent of the MEL?
The one who snags #1 brake and #4 wheel on arrival. Have you no idea of the turnaround time? Couldn't the maintenance guy at the last station have made a call.
The crew that have pissed off the aircraft without having even making a nil entry in the logbook, not even attempted to begin a coupon. You increase the brightness on EICAS and there is a message or two there.
When at the end of a twelve hour nightshift, been at it all night and the crew departing the first flight of the day start complaining no maintenance is ever being done at night because the defect they wrote up yesterday is still deferred today.
The ones who expect an immediate answer to a defect? Do you know how many aircraft/engine types, the myriad systems we are expected to have a 'reasonable' general knowledge of. If I need to leave the flight deck to access some literature it's because I'm trying to give you an accurate response. Otherwise if you prefer bull****, I have no end of crap I can digress.
Crew, tech n cab, who expect every part that makes up an airliner is available at every station, so it can be replaced by you at their convenience.
Etc etc etc ..... BUT generally speaking, most crew a very reasonable people, especially these days because they're more affected by the ridiculous constraints put on all of us by our management.
C.