Conversation so far:
what was Frank sinatra's style?
frank Sinatra was known for his immaculate sense of style
what did Frank sinatra like to wear?
custom-tailored tuxedos and stylish pin-striped suits, which made him feel wealthy and important
what colors did frank sinatra wear on his custom-tailored tuxedos and stylish pin-striped suits, which made him feel wealthy and important?
What was Frank sinatras' personality like?
Frank Sinatra had mood swings

Question: why did he have mood swings?
Self-contained rewrite: why did Frank sinatra have mood swings?