Manners are like rules and most people have problems with them, they are there to help not hurt you. Good manners help people feel more confident in society's eyes, they are not there to be used to make other people feel ignorant. One of the worst forms of bad manners is making someone feel bad about himself. Ignorance and meanness are unattractive qualities. Don't act like you've never seen a plate of food before.
Art is a form of expression.
It adds to culture and enriches the mind. Being able to view and analize the concept of the piece in many perspectives is quite easy if one's imagination is left to roam. The beauty and style of each piece has a meaning some deeper than others. Yet some have more definition than you would ever think possible to fit on a piece of canvas. So go ahead polish up and take time out to better understand and appreciate art.