I was in the Tate Gallery, London, the other day and I saw a sign warning visitors not to touch a partially completed "installation".   It was hard to tell where the barrier around the "installation" ended and the chef d'oeuvre itself began.   Now that the Tate has an entire second gallery in London for that sort of nonsense (not to mention branch offices in Liverpool and St Ives), I wish they'd stop wasting space on it in the main building.