Well what makes good art or bad art is quite a difficult question to answer. Though Rorr's answer is quite a good one imo

For example take this picture 'Dust Heads' depicting two junkies high on Angel Dust painted in 1982 by Basquiat.

Would you say in your opinion that this is good or bad art?

Would you be surprised if I told you the current owner paid close to 50 million dollars for it a few years ago at a Christie's auction in New York? Obviously the purchaser considered it to be quite good or maybe he/she just seen it as an investment piece. Though it's not really to my own personal taste there is something that I do like about it. Probably not 50 million dollars worth of like though. Hard to say whether it's good or bad art. Some like it, some don't. Some think it's worth millions, others may discard it as trash if they didn't know its true value.

Does it seem better or worse art knowing its value?