Art is a lot more than the visuals you see or the acting for example. Maybe it helps you to know, that any "artwork" gives you a clear view into the point of time, when it was created. If you understand this, you can better grasp what the artist wants carry over with his work, why the artist has done this and how this art influenced other artist's and society.

Just two examples to make it clear:

High Art vs Low Art (kitsch):

https://www.documenta.de/en/retrospective/documenta_5

Going new Ways and influence Art (kurt schwitters):

http://www.independent.co.uk/arts-entertainment/art/features...

https://en.wikipedia.org/wiki/Kurt_Schwitters#Influences

And two Sites, that can give you a good sart:

http://onlinekurs.staedelmuseum.de/en/

https://www.moma.org/learn/moma_learning