A friend recently sent this video to me. It's beautiful; it just illustrates how art can take on so many different forms.
Really good art should make you feel something, sounds so cliche but it's key. The concept of "good art" is so subjective, but I see when people are inspired by what they see on the walls. They ask questions, they move up close, they smile, or they frown, but it produces an effect.
I remember the Lucy McLaughlan exhibit at FIFTY24SF; I walked in and I couldn't believe my eyes. She used the space so well, her wall installations interacted with the paintings to make it look as if a drop of water was magnifying that particular spot, (which was the painting). I couldn't hep but laugh. It was all so intense that I had a physical reaction to the work.
I once heard of a study they did regarding the physical effect art has on the human body. They studied travelers going to the Louvre; the conductors of the study monitored visitors physical reactions and found that heart rate increased, some experienced nausea, and some experienced bouts of unexplained euphoria. I have been looking for the article all day but it's nowhere to be found so, I can't back this up with concrete evidence... take it with a grain of salt. Regardless, I stand behind the idea that art, real art, makes you feel something.