Art seems to be very difficult to understand for the common person... who isn't into the arts... I wouldn't exactly say common sense... more like, ability to appreciate the art?
When I really started to appreciate how things looked... you kind of learn a set of rules that come with art.
Some common rules, for example, with sig making that I learned from my graphics site, include:
1) The main Part of the signature (Ex: the hulk... more specifically his face)
Must be easy on the eyes, and it must stand out the MOST out of anything on the signature. It has to be the heart... the main FOCUS.
2) The signature has to make sense
3) The signature must have a "flow" that moves the sig in a general direction that is appealing to the eye... example, in my starcraft sig... doesn't it feel like the light is "coming down" on the marine?
There are SO many more.
And of course, people who break these rules, and make sick signatures... well, that is true art
