The title of Radiohead’s b-side “Worrywort” is a phrase of uncertain origin. The OED claims the first usage of the phrase, spelled “worrywart,” appeared on page 177 of Ivan Belknap’s 1956 book Human Problems of State Mental Hospitals: “The persevering, nagging delusional groupwho were termed ‘worry warts’, ‘nuisances’, ‘bird dog’, in the attendants’ slang.” Other reference sources claim the phrase first appeared in J. R. Williams’s comic strip “Out Our Way” in 1956.
A portion of the song’s lyrics read:
Take a look around,
There’s candles on the cake,
On what might have been,
The road you should have took,
The tradition of putting candles on cakes seems to have developed separately in both ancient Greece and medieval Germany. The association of cakes with candles and birthdays appears to have started in Germany, however. Though for elementary school teachers, this page is a good resource for summarized information on birthdays. Though hosted on a commerical site, this history of birthdays is informative.