There are all sorts of tattoos gor example that number you get in a concentration camp or a gangs-tattoo. Prisoners take tattoo after tattoo but it is frequently out of boredom.
The average tattooshop isn't famous because of the artists at work. More personal it can be for the receiver because it's on his/her skin but so it bodypaint. In both cases the canvas is the body.

In both cases an artist is needed.