It is illegal in most cases, and graffiti at the core...
Graffiti Art
Graffiti art has been a part of urban culture dating back to the late 1960s. It is an art form that has spread through the world and gained a lot of popularity; it can be seen on clothing, backpacks, modern art galleries, and yes walls and other public places. It is illegal in most cases, and graffiti at the core typically has political messages or just expresses the artist feelings and creativity by using the alphabet, shapes, and characters in some cases. The whole purpose behind graffiti is to get your name "up" and be noticed by many, to gain fame by going against what society tells you to do, and to in a way give a metaphorical middle finger to the higher government powers at being.