Shigeru Miyamoto got the idea for Boo from the wife of his co-worker and close friend Takashi Tezuka, as she is shy but one day got very angry at him for coming home late from work.
Lemme guess, she got angry when he turned his back to her
Takashi- Avenge me Shigeru. You should've seen her fatal fury.
Shigeru- I will....with the power of video games.
In addition, Boo was originally named Boo Diddley in Super Mario Bros. 3, after the late, great musician Bo Diddley.