The title of this song alludes to Thom Yorke wishing he wasn't so sensitive.
According to Q magazine April 2008, the whoosing sound effects and ghostly whale-song howls were improvised by guitarists Jonny Greenwood and Ed O'Brien. They were only added at the Manor studios, 5 months after recording had started.
The Four Tops' "I Can't Help Myself (Sugar Pie Honey Bunch)" was written by the Motown team of Lamont Dozier, Brian Holland and Eddie Holland. The phrase "Sugar pie, honey bunch" was something Dozier's grandfather used to say when he was a kid.
Who writes a song about a name they found in a phone book? That's just one of the everyday things these guys find to sing about. Anything in their field of vision or general scope of knowledge is fair game. If you cross paths with them, so are you.