Almost any double entendre song is happy: Maid of Australia, The Game of All Fours, Cruising 'Round Yarmouth. Drinking songs are pretty upbeat, too: When Jones' Ale Was New, Good Ale, Old Dun Cow, Little Brown Jug. While they can leave folks feeling down, sex and booze -- in the moment -- tend to be uplifting, so there are piles of songs that capture that part of the experience.