Elephant in the room
This expression originated in America during the mid-20th century and is a hyperbole that describes a patently obvious but socially embarrassing or awkward situation (like having an elephant in the room) that one simply ignores or avoids. Marcel Berlins, barrister turned broadcaster and journalist, in 2006 wrote in the Guardian, “It is the phrase I most hate in the whole world”. Clichés can have that effect on people. In America, the expression is an elephant in the living room. The British usage does not specify any particular room and, much to Berlins’ horror, probably extended its usage. The OED cites a first appearance in print in The New York Times June 1959. “Financing schools has become a problem about equal to having an elephant in the living room. It’s so big you can’t just ignore it.” This is not quite its current meaning but was obviously the precursor.