Art?

I don't know anything about classical works of art. My range of knowledge about artists doesn't extend far past Van Gogh or Picasso. And that's only because we learned about them in elementary school. The only point I could really argue is to as why people value most works of art. Picasso paintings, as well as many, many other paintings made by other artists are abstract and make no sense upon first glimpse. They can be worth more and viewed as better than some paintings that are completely realistic. What makes one of these paintings a 'work of art'? It seems like any child can dip their fingers in paint and go crazy on a canvas and make a drawing that an expert would deem worth millions. As a matter of fact, I'm sure I've seen several cartoons and shows where this scenario has been documented. It doesn't make sense to me as to what degree is considered to make a work of art a 'work of art'. Perhaps there are underlying metaphorical references that people see in the paintings. It could also just depend on who's critiquing it. One person will see it as a masterpiece while another sees it as a piece of junk (which it probably is). I guess art could be just like almost anything else on this earth, a matter of opinion.