Life of Riley
This means a comfortable life, free from worry or anxiety.
No one seems to agree on where it came from. It dates to the early 1900s. Later, there was a radio show, a TV show, and a couple of movies that used the title.
Why I Looked It Up
It was a clue in the NY Times Mini Crossword. “Living the life of _____.” I knew it intutively, but had no idea why. (Still don’t, honestly.)