Heidegger says that art exists not in and of itself but as something we engage in. As we think about the meaning of a work of art, the art exists as art, but once we feel we understand the meaning, the art is dead to us.
As such I enjoy art in terms of length of time. There are some Dali's that are still alive for me; and I go back to them in my mind. There are portraits by Raphael I still can't shake out of my head. Then there's Jackson Pollock, who I spent about 10 seconds watching do his work before I said 'fuck this guy and everything he does'.
This lasted as art for me for about 15 seconds; which is, as is said above, all you really need for 'lobby art'.