Should art be intentional and representational in order to be called art?

Webster defines art as the making or doing by people of things that have form and beauty. So if that is the case I don't think art has to be intentional to be called art. I mean people have their own views of what is beautiful. For instance, if a person takes a pile of junk and sticks a price tag on it, to them its art, to other people its a pile of junk. To the person who put it together, the pile has form,beauty, intentional and it can be representational right? Why does art have to be something that is painted on a canvas or carved out of stone supposed to represent anything? Art should be what the artiest feels when doing the art. What if the art we look at today was made by mistakes? What if the artiest was trying to paint or draw something and thought that maybe if I did this here or that there and all of a sudden came up with something new? Is that intentional? No one knows but the artiest. If what Webster said about art is true then art is all around us. Think about it. The computer you us has form and lines, so why do we not call it art? What about the chair you are in? Both were intentional. So why don't we call it art? I guess it is up to the person who looks at a painting or statue to make the call.