Art?

What is art? Is it based on personal opinion? Does it have some standard? I think so. If it doesn't then the word art has no meaning. I mean if art is based on personal opinion and as long as somebody claims that it is art that makes it art to that person then i claim that everything is art, and once again it no longer means anything. Is art any expression of feelings? If so then i hold that Hitler was the greatest artist of all time, because he made the biggest impression of hatred and cruelty and was responsible for the death of millions. Once again i don't think so. I think that art must be several things. It must meet some criteria, some standard. This standard includes
1. An expression of somebody's emotions- it doesn't have to the artists expression of feelings but it must be somebody's.
2. It must be created with the intent of being presented as an expression of feeling. (i.e. it cannot be an item that is created for practical purposes, for example if i make a desk for the expressed purpose of writing an essay and the desk is created with that expressed purpose the driving force behind the desk then it is not art). It also be presented to someone (including God) for example if i create a beautiful sandcastle on an uninhabited island and it will be washed away, if i don't present to anyone then it is not art. However as soon as i present to God then it becomes art.
This post will grow and this list is right now not exhaustive and it will be added to for sure as i think more about it.
3.