be concerned with relatively trivial matters while ignoring the serious or disastrous events going on around you
This phrase comes from the Roman biographer and historian Suetonius' description of the behaviour of the Roman emperor Nero during the great fire that destroyed much of Rome in AD 64.
fit as a fiddle
in very good health
hang up your fiddle when you come home
cease to be cheerful or entertaining when you are in the company of your family - chiefly US
on the fiddle
engaged in cheating or swindling – informal
Fiddle was late 19th-century US slang for a swindle.
play second fiddle to
take a subordinate role to someone or something
The expression derives from the respective roles of the fiddles or violins in an orchestra. Both play first fiddle and play third fiddle are much less common. The implication of playing second fiddle is often that it is somewhat demeaning.
1998 - Times - In A Yank at Oxford, she played second fiddle to Vivien Leigh, which never got anyone very far.