One thing that ALWAYS bothers me because it ALWAYS happens is the windscreens and other windows of vehicles seen on TV and in movies. They are, with very few exceptions, too clean to give the authenticity the director is looking for.
Whether low-key TV drama or big blockbuster film, the vehicle being shown - usually with the hero or some shadowy stalker-type figure driving - has a gleaming windscreen. This is because the production company hired the appropriate vehicle needed (from a car-hire firm if a contemporary setting - or vintage car-hire firm specialising in older cars) and the company they use pride themselves on sending out cars/vehicles of a high standard and this obviously includes polishing the windscreen.
The production company has the appropriate vehicle for a minimum amount of time to save on costs and to further save on costs, they don't bother to put a film of dust on the windscreen before having the wipers swipe off the arc of cleanliness you'll all no doubt be seeing on your own cars next time you get in to them (exception being is you've just had it through the car-wash - obvs). This is to further save hire-car costs by not sending back the vehicle in a 'dirty' state and they don't have time, or the staff, to send it through a car-wash. The costumes are always authentic looking, the make-up artist and hairdresser has done a superb job but then you get a glaring continuity error by having a car - sometimes having driven through a desert or being driven for days on end - with a shiny freshly polished windscreen.