Moar funny pictures
Ok ok there is a point to this…
Engaging the user’s eye/mind to fill in the missing details is a great technique used by designers to add interest and “movement” to a piece of work – be it a graphical composition, an object or a space. Our eyes are especially good at joining lines and finding corners, and we seem to find this “work” fun and interesting. Often all we need is a few subtle hints to pique our interest. And it probably operate more so on a subconscious level than we are aware of.
Making the user work too hard to extract useful information is not good of course.