A personality can be caused by a difference in

People vary in personality and social behaviour. It is generally accepted that some of this variation is due to differences in genes and some to “environment”—that is, to differences in people's experiences. This chapter is about the latter source of individual differences, the variation that is not due to genes.

answer: the feeling it gives you when you look at it.

explanation:

in every single medium of art, you are supposed to feel something that makes it art. like how a song can make you cry, or how a photograph can make you nostalgic. art is very important for expressing yourself as well, when you are happy, sad, depressed, or angry.