Happy as Larry
This expression originated in Australia or New Zealand during the late 19th century. There are two contenders for its origin. The first is the Australian boxer Larry Foley who retired a wealthy man in the 1870s after being unbeaten in 32 contests, the second is that it derives from larrikin, a largely Australian expression for a rowdy street hooligan. Larrikins are generally boisterous, intoxicated and therefore happy.