Body art is like bacon apple pie. You have butter, sugar, water, flour, apples and BACON but if you don't have enough of something, it isn't quite right. You still have bacon apple pie, but it's just not very good.
So with body art you build a piece with ingredients of contrast and composition. Lights / darks ... hard lines or edges / soft lines / edges ... warm colors / cool colors ... texture contrast ect. ... An example of a piece without some of these ingredients would be traditional tattoos, basically make some lines of similar thickness and fill it in with some color. It's why they look flat and in my opinion quite boring.
The composition or content of the piece is based on where the piece is going and how it compliments someones flow of anatomy. For example a business card size tattoo in the middle of someones bicep or people who get random things stacked on top of each other or placed randomly does not make for good art.
After you try to educate someone on art and tattooing and they still go through with getting something mediocre it is really discouraging and makes me wonder why do I even bother trying.
I have a great appreciation admiration and respect for people who take the time to think before they get tattooed. The ones who do not make their decisions out of convenience, obligation or defiance. The ones who truly shop for an artist instead of just a tattooer.
Love yourself, love your artist.