A reader asked me about the origin of the expression "happy as Larry", which means being very happy. It looks like nobody is entirely sure. It was first recorded in 1905 and according to abc.net, "Sidney J Baker, in his classic book The Australian Language says that while we can’t know for sure, it’s possible that it comes from an Australian boxer named Larry Foley. His dates are 1847 to 1907. Why he was regarded as a happy pugilist is lost in the mists of time, but, apparently he was."
In French, we’d say gai(e) comme un pinson (joyous as a chaffinch), heureux/heureuse comme un roi/une reine (happy as a king/a queen), heureux/se comme un poisson dans l’eau (happy as a fish in water), etc.
I also read the Larry in question might be Lazarus, who was supposedly raised from the dead, which is reason enough to be happy.