Why do people mark themselves with tattoo's?

Tattoos are a way of expressing oneself. Just like writting or drawing. Each tattoo carries a certain meaning or message, many have multiple meanings. Tattoos=art. Take stars for example, one of the most popular symbols, can represent happiness, luck, hope, a journey...pretty much whatever you think of when you think of a star. A tattoo is something that you can make personal just by having a story or a view of what you are getting and why. For example when my son is born i am going to take his handprint and turn it into a tattoo with his name going thru it. Symbolizing to me the journey of life and the neverending love that i will have with him.