When using film airport security controls.
All the time the existence of different standards for things which shouldn't require that. For example why so many cables to use Pocket Wizards with different flash/camera combinations, why a lens manufacturer produces a profile for correcting distortion of its lenses in Lightroom, another in Photoshop but you need to run a certain version, and having the same profile for any of the lenses in Gimp is a nightmare...
The paranoia against cameras many countries developed after 9.11 (I know, I know, terrorists take pictures of models in parks all the time and they use soft-boxes instead of umbrellas).
Not being able to print a large format colour film without passing through a digital scan.
Collectors inflating the value of old cameras they buy and don't even use...
GLF